Conjugated psychotropic drugs and uses thereof

ABSTRACT

Novel chemical conjugates of psychotropic drugs and organic acids, uses thereof in the treatment of psychotic and/or proliferative disorders and diseases and as chemosensitizing agents, and their syntheses are disclosed. The organic acids are selected to reduce side effects induced by the psychotropic drugs and/or to exert an anti-proliferative activity.

RELATED APPLICATIONS

This Application is a divisional of U.S. patent application Ser. No.10/808,541, filed Mar. 25, 2004, now U.S. Pat. No. 7,544,681, which is acontinuation-in-part of PCT Patent Application No. PCT/IL02/00795 filedSep. 29, 2002, which claims the benefit of U.S. Provisional PatentApplication No. 60/324,936, filed Sep. 27, 2001. The contents of theabove Applications are all incorporated by reference.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to novel chemical conjugates ofpsychotropic drugs and organic acids, and uses thereof. Moreparticularly, the present invention relates to novel chemical conjugatesof psychotropic drugs (which may also have anti-proliferative activityand/or chemosensitization activity), and organic acids selected so as toreduce side effects induced by the psychotropic drugs and/or so as toexert an anti-proliferative activity, and uses thereof in the treatmentof psychotropic and/or proliferative disorders and diseases and inchemosensitization. The novel chemical conjugates of the presentinvention are characterized by minimized adverse side effects ascompared to prior art psychotropic drugs.

Psychotropic drugs are pharmacological agents that act mainly in thecentral nervous system (CNS) by modulating neuronal signalstransduction. Psychotropic drugs are therefore known, and are referredto herein, as pharmacological agents that exert an activity in the CNSto thereby treat a CNS associated impairment, and include, for example,anti-psychotic drugs, anti-depressants, anti-convulsants, anxiolytics,inhibitors of brain derived enzymes and the like.

Unfortunately, the administration of psychotropic drugs is typicallyassociated with adverse side effects, such as seizures, headaches,fatigue, hyperactivity, dizziness, and many more, which severely limittheir use. A comprehensive list of such side effects can be found, forexample, in “The Merck Manual of Medical Information” (Merck & Co.Inc.).

Neuroleptic drugs, for example, which are also known as neurolepticagents or neuroleptics, are classical anti-psychotic drugs that arewidely used in the treatment of central nervous system psychoticdiseases and disorders, such as schizophrenia. The anti-psychoticefficacy of neuroleptics is attributed to their ability toantagonize/block central dopamine receptors. The neuroleptic drugs areknown as typical anti-psychotic drugs and include, for example,phenothiazines, amongst which are aliphatics (e.g., chlorpromazine),piperidines (e.g., thioridazine) and piperazines (e.g., fluphenazine);butyrophenones (e.g., haloperidol); thioxanthenes (e.g., flupenthixol);oxoindoles (e.g., molindone); dibenzoxazepines (e.g., loxapine) anddiphenylpiperidines (e.g., pimozide).

However, the administration of currently available neuroleptic drugs isfrequently associated with adverse side effects. It is well known in theart that neuroleptic agents induce extrapyramidal symptoms, whichinclude rigidity, tremor, bradykinesia (slow movement), and bradyphrenia(slow thought), as well as tardive dyskinesia, acute dystonic reactionsand akathasia. In fact, about 5% of patients that are treated withchronic therapy of neuroleptic drugs for over a year develop pathologyof tardive dyskinesia.

A different class of anti-psychotic drugs includes the atypicalanti-psychotics. Atypical anti-psychotic drugs have a receptor bindingprofile that includes binding to central serotonin 2 receptors (5-HT2)in addition to dopamine D2 receptors. Atypical anti-psychotic drugsinclude, for example, clozapine, olanzapine and risperidone, and aregenerally characterized by high anti-serotonin activity and relativelylow affinity to dopamine D2 receptors. Some atypical anti-psychoticdrugs, such as clozapine, are known to further antagonize adherenic,cholinergic and histaminergic receptors.

Unlike the neuroleptics, atypical anti-psychotics cause minimalextrapyramidal symptoms and thus rarely cause tardive dyskinesias,akathasia or acute dystonic reactions. However, the administrationthereof involves other side effects such as increase of body weight,mood disturbances, sexual disfunction, sedation, orthostatichypotension, hypersalivation, lowered seizure threshold and, inparticular, agranulocytosis.

The sever side effects that are associated with both typical andatypical anti-psychotic drugs, also referred to herein asanti-psychotics, establish a major limitation to their use and extensiveefforts have been made to develop anti-psychotic drugs devoid of theseside effects.

U.S. Pat. No. 6,197,764 discloses chemical conjugates of clozapine (anatypical anti-psychotic drug) and a fatty acid of 12-26 carbon atoms,preferably 16-22 carbon atoms. These conjugates are characterized byextended therapeutic effectiveness, which permits administration oflower doses thereof to yield an anti-psychotic therapeutic effect andthereby reduce the chances of developing serious side effects. Hencethese conjugates are beneficial and advantageous over non-conjugatedatypical anti-psychotic drugs. However, U.S. Pat. No. 6,197,764 fails todisclose such advantageous conjugates that include other anti-psychoticagents and is further limited to conjugates including long-chain fattyacids. It should be mentioned that ester conjugates of otheranti-psychotics, mainly neuroleptics, and long-chain fatty acids arewell known in the art. Nevertheless, such conjugates are aimed mainly atfacilitating the brain penetration of the drug and are not designed toactively reduce or prevent side effects.

U.S. Pat. No. 3,966,930 discloses fluoro-substituted phenothiazinederivatives that have pronounced neuroleptic properties and a relativelylow degree of undesired side effects. However, while some of the claimedfluoro-substituted phenothiazine derivatives of U.S. Pat. No. 3,966,930include an acyl radical that has 1-17 carbon atoms in its chain, theexperimental data is limited to phenothiazine derivatives that includeonly acyl radicals derived from either oxalic acid or maleic acid (i.e.,organic acids that include 2 and 4 carbon atoms, respectively). Thedisclosed phenothiazine derivatives have longer therapeutic effect ascompared to other known neuroleptics and are therefore characterized bya relatively low degree of induced side effects. The prolongedtherapeutic effect of these compounds is mainly attributed to thephenothiazine substituents (e.g., fluoro and trifluoromethyl) whiletheir conjugation with the organic acids is aimed chiefly atfacilitating their pharmaceutical formulation.

Recent studies on the development of extrapyramidal symptoms as a resultof treatment with psychotropic drugs, mainly neuroleptics, havesuggested a mechanism that involves an imbalance in the dopaminergicreceptors D1 and D2, which is further accompanied by decreased activityof the γ-aminobutyric acid (GABA) system in the brain.

GABA is an important inhibitory neurotransmitter in the brain, which isknown to affect mood stabilizing activity, anxiolytic activity andmuscle relaxant activity, and is further known to be related to somecentral nervous system disorders and diseases. The recent studies onextrapyramidal symptoms suggest that GABA agonists may be further usedto reduce neuroleptic-induced side effects and thus have an additionaltherapeutic potential.

Previous studies have already suggested that GABA agonists can interferewith other brain neurotransmitters and, in particular, with the dopaminesystem. Thus, it was found that GABA agonists can antagonize theneuroleptic-induced increase of dopamine receptors sensitivity and aretherefore capable of improving neuroleptic-induced dyskinesia [1].Furthermore, it was found that some known direct GABA agonists (e.g.,muscimol and SL 76002) cause a biphasic effect on haloperidol-inducedcatalepsy, such that while low doses of the agonist inhibit thestereotypic catalepsy behavior, high doses of the agonist potentiate thehaloperidol-induced catalepsy. Other studies have reported that GABAagonists further induce anti-convulsive activity [2].

The use of GABA agonists is limited since they include hydrophilicfunctional groups (e.g., a free carboxylic acid group and a free aminogroup) and therefore do not readily cross the blood brain barrier (BBB).However, it was found that chemical conjugation of such compounds withfatty amino acids or peptides could substantially facilitate theirpassage across the blood brain barrier (BBB) [3].

Indeed, U.S. Pat. Nos. 3,947,579; 3,978,216; 4,084,000; 4,129,652 and4,138,484 disclose that GABA-like compounds (compounds that arepharmacologically related to GABA) which are known to cross the bloodbrain barrier, such as γ-hydroxybutyrolactone, γ-hydroxybutyrate,aminooxyacetic acid, 5-ethyl-5-phenyl-2-pyrrolidone,1-hydroxy-3-amino-2-pyrrolidone and β-(4-chlorophenyl)-γ-aminobutyricacid, when co-administered with neuroleptic drugs, allow the use ofsomewhat lower doses of neuroleptic drugs to obtain the sameanti-psychotic effect as obtained with higher doses of neuroleptic drugwithout administering these GABA-like compounds and, at the same time,somewhat reduce extrapyramidal side effects. The same anti-psychoticeffect is said to be obtained although lower doses of neuroleptic drugsare used because the GABA-like compounds are said to potentiateanti-psychotic activity of the co-administered anti-psychotic drug.

Recent studies revealed that some psychotropic drugs and, in particular,the phenothiazines, further exert a potent anti-proliferative activityin different cell lines, such as neuronal cells, glial cells, melanomacells, breast cells, colon cells, prostate cells, lymphoma and leukemia,as well as in primary human keratocytes [4]. The “new half mustard typephenothiazines”, which is known to exert a specific inhibitory effect oncalmodulin, were tested by the National Cancer Institute (NCI). Theanti-proliferative activity of the phenothiazines was observed in the invitro screen of 60 different human cancer cell lines. Somephenothiazines further showed significant inhibition of tumor growth inanimal models. These findings are consistent with the low frequency ofcancer occurrence in schizophrenic patients on neuroleptic medication,as compared with the general population.

WO 02/43652, which is incorporated by reference as if fully set forthherein, teaches the use of various typical and atypical psychotropicagents in the treatment of proliferative diseases. In particular, WO02/43652 teaches that cyclic psychotropic agents (e.g., tricyclic,bicyclic and monocyclic) can serve as effective agents in the treatmentof numerous tumors, including glioma, melanoma, neuroblastoma, colon,lung and prostate cancers, as well as in the treatment of multi drugresistant (MDR) cancer cells, such as B16 melanoma cells (known to beresistant to doxorubicin and colchicine) and Neuroblastoma (SH-SY5T,resistant to 5-FU and doxorubicin). Moreover, apart from teaching theactivity of psychotropic agents in the treatment of MDR cancer, WO02/43652 further teaches the use of the psychotropic drugs aschemosensitizers, namely, as compounds that effectively sensitize cancercells, particularly MDR cancer cells, to cytotoxic drugs.

However, although the teachings of WO 02/43652 are highly advantageous,particularly with respect to the anti-proliferative andchemosensitization activity of psychotropic agents in the treatment ofMDR cancer, the use of these psychotropic agents is highly limited bythe adverse side effects induced thereby.

Butyric acid (BA) and 4-phenylbutyric acid (PBA), of which GABA is aderivative, are also known to act as differentiating andanti-proliferative agents in a wide spectrum of neoplastic cells invitro [5]. Both the butyric acid and the 4-phenylbutyric acid are knownas pleotropic agents and one of their most notable activities is thereversible increase of the acetylation level in nuclear histones, whichleads to chromatin relaxation and changes in transcription activity [6].It is assumed that this mechanism of action is further related to theanticancer activity of butyric acid and the 4-phenylbutyric acid.

Thus, the prior art teaches the use of psychotropic drugs in thetreatment of central nervous system disorders and diseases, as well asin the treatment of proliferative disorders and diseases such asmalignant and benign tumors and MDR cancer, as anti-proliferative agentsand as chemosensitizers. The prior art further teaches the use of GABAagonists (including GABA itself) as potential agents for reducingneuroleptic-induced side effects as well as the use of butyric acid andderivatives thereof as anti-proliferative agents.

Nevertheless, there is still a widely recognized need for, and it wouldbe highly advantageous to have, psychotropic drugs characterized byimproved therapeutic activity and yet reduced side effects, which canalso serve as anti-proliferative drugs and as chemosensitizers.

SUMMARY OF THE INVENTION

According to the present invention there are provided (i) chemicalconjugates of psychotropic drugs and organic acids selected to reducethe side effects induced by the psychotropic drugs and/or to exertanti-proliferative activity; (ii) chemical conjugates of psychotropicdrugs and GABA agonists (including GABA itself); (iii) chemicalconjugates of psychotropic drugs and anti-proliferative agents; (vi)methods for their synthesis; (v) use thereof in the treatment and/orprevention of psychotropic disorders and diseases while reducing theside effects characteristic of conventional psychotropic drugs; (v) usethereof in the treatment and/or prevention of proliferative disordersand diseases; and (vi) use thereof as chemosensitizing agents.

It is shown herein that such chemical conjugates of psychotropic drugsare characterized by minimized adverse side effects (e.g.,extrapyramidal symptoms), enhanced psychotropic therapeutic activity andanti-proliferative activity and by chemosensitization activity. It isfurther shown herein that such chemical conjugates unexpectedly providesynergistic effects as compared to their parent compounds both withrespect to their therapeutic effects and with respect to theminimization of side effects.

Thus, according to one aspect of the present invention there is provideda chemical conjugate comprising a first chemical moiety covalentlylinked to a second chemical moiety, wherein the first chemical moiety isa psychotropic drug residue and further wherein the second chemicalmoiety is an organic acid residue that is selected so as to reduce sideeffects induced by the psychotropic drug when the psychotropic drug isadministered per se and/or to exert anti-proliferative activity.

According to another aspect of the present invention there is provided apharmaceutical composition comprising, as an active ingredient, thechemical conjugate of the present invention and a pharmaceuticallyacceptable carrier.

The pharmaceutical composition of the present invention is preferablypackaged in a packaging material and is identified in print, on or inthe packaging material, for use in the treatment of a psychotropicdisorder or disease, for use in the treatment of a proliferativedisorder or disease and/or for use in chemosensitization, in combinationwith a chemotherapeutic agent and/or in a medical condition for whichchemosensitization is beneficial.

According to yet another aspect of the present invention there isprovided a method of treating or preventing a psychotropic disorder ordisease in a subject, the method comprising administering to the subjecta therapeutically effective amount of the chemical conjugate of thepresent invention.

According to further features in preferred embodiments of the inventiondescribed below, the psychotropic disorder or disease is selected fromthe group consisting of a psychotic disorder or disease, an anxietydisorder, a dissociative disorder, a personality disorder, a mooddisorder, an affective disorder, a neurodegenerative disease ordisorder, a convulsive disorder, a boarder line disorder and a mentaldisease or disorder.

According to still further features in the described preferredembodiments the psychotropic disorder or disease is selected from thegroup consisting of schizophrenia, paranoia, childhood psychoses,Huntington's disease, Gilles de la Tourette's syndrome, depression,manic depression, anxiety, Parkinson disease, Alzheimer disease andepilepsy.

According to still another aspect of the present invention there isprovided a method of treating or preventing a proliferative disorder ordisease in a subject, the method comprising, administering to thesubject a therapeutically effective amount of the chemical conjugate ofthe present invention.

According to further features in preferred embodiments of the inventiondescribed below, the proliferative disorder or disease is selected fromthe group consisting of a brain tumor, a brain metastase and aperipheral tumor.

According to still further features in the described preferredembodiments the proliferative disorder is cancer, such as multidrugresistant cancer.

According to an additional aspect of the present invention, there isprovided a method of chemosensitization. The method comprisesadministering to a subject in need thereof a chemotherapeuticallyeffective amount of one or more chemotherapeutic agent(s) and achemosensitizing effective amount of the chemical conjugate of thepresent invention.

According to further features in preferred embodiments of the inventiondescribed below, the subject has cancer such as multidrug resistantcancer.

According to further features in preferred embodiments of the inventiondescribed below, the second chemical moiety is covalently linked to thefirst chemical moiety via an ester bond selected from the groupconsisting of a carboxylic ester bond, an alkyoxy carboxylic ester bond,an amide bond and a thioester bond.

According to still further features in the described preferredembodiments the second chemical moiety is selected from the groupconsisting of an anti-proliferative agent residue, an analgesic residueand a GABA agonist residue.

According to still further features in the described preferredembodiments the psychotropic drug has an anti-proliferative activity.

According to still further features in the described preferredembodiments the psychotropic drug has a chemosensitization activity.

According to still further features in the described preferredembodiments the psychotropic drug residue is selected from the groupconsisting of a phenothiazine residue and a phenothiazine derivativeresidue.

According to still further features in the described preferredembodiments the psychotropic drug residue is an anti-psychotic drugresidue.

According to still further features in the described preferredembodiments the anti-psychotic drug residue is selected from the groupconsisting of a typical anti-psychotic drug residue and an atypicalpsychotic drug residue.

According to still further features in the described preferredembodiments the psychotropic drug residue is selected from the groupconsisting of an anxiolytic drug residue, an anti-depressant residue, ananti-convulsive drug residue, an anti-parkinsonian drug residue, anacetylcholine esterase inhibitor residue, a MAO inhibitor residue, atricyclic psychotropic drug residue, a bicyclic psychotropic drugresidue, a monocyclic psychotropic drug residue, a phenothiazineresidue, a benzodiazepine residue and a butyrophenone residue.

According to still further features in the described preferredembodiments the psychotropic drug residue is selected from the groupconsisting of a chlorpromazine residue, a perphenazine residue, afluphenazine residue, a zuclopenthixol residue, a thiopropazate residue,a haloperidol residue, a benperidol residue, a bromperidol residue, adroperidol residue, a spiperone residue, a pimozide residue, apiperacetazine residue, an amilsulpride residue, a sulpiride residue, aclothiapine residue, a ziprasidone residue, a remoxipride residue, asultopride residue, an alizapride residue, a nemonapride residue, aclozapine residue, an olanzapine residue, a ziprasidone residue, asertindole residue, a quetiapine residue, a fluoxetine residue, afluvoxamine residue, a desipramine residue, a paroxetine residue, asertraline residue, a valproic acid residue, a temazepam residue, aflutemazepam residue, a doxefazepam residue, an oxazepam residue, alorazepam residue, a lormetazepam residue, a cinolazepam residue, aflutazolam residue, a lopirazepam residue, a meprobamate residue, acarisoprodol residue, an acetophenazine residue, a carphenazine residue,a dixyrazine residue, a priciazine residue, a pipothiazine residue, ahomophenazine residue, a perimetazine residue, a perthipentyl residue, aflupentixol residue, a piflutixol residue, a teflutixol residue, anoxypethepin residue, a trifluperidol residue, a penfluridol residue, ameclobemide residue, a norclomipramine residue, an amoxapine residue, anortriptyline residue, a protriptyline residue, a reboxetine residue, atacrine residue, a rasagiline residue, an amatadine residue, aphenobarbital residue and a phenytoin residue.

According to still further features in the described preferredembodiments the GABA agonist residue is selected from the groupconsisting of a (±) baclofen residue, an γ-aminobutyric acid (GABA)residue, a γ-hydroxybutyric acid residue, an aminooxyacetic acidresidue, a β-(4-chlorophenyl)-γ-aminobutyric acid residue, anisonipecotic acid residue, a piperidine-4-sulfonic acid residue, an3-aminopropylphosphonous acid residue, an 3-aminopropylphosphinic acidresidue, an 3-(aminopropyl)methylphosphinic acid residue, a1-(aminomethyl)cyclohexaneacetic acid residue (gabapentin), a4-amino-5-hexenoic acid (y-vinyl GABA, vigabatrin) and an3-(2-imidazolyl)-4-aminobutanoic acid residue.

According to still further features in the described preferredembodiments the anti-proliferative agent residue is selected from thegroup consisting of a butyric acid residue and a 4-phenylbutyric acidresidue.

According to still further features in the described preferredembodiments the organic acid residue has a general formula —R—C(═O)—wherein, R is selected from the group consisting of a substituted ornon-substituted hydrocarbon residue having 1-20 carbon atoms, asubstituted or non-substituted hydrocarbon residue having 1-20 carbonatoms and at least one heteroatom selected from the group consisting ofoxygen, nitrogen and sulfur and R₁, whereas, R₁ is a residue of ageneral formula —Z—C(═O)O—CHR₂—R₃ wherein, Z is selected from the groupconsisting of a single bond, a substituted or non-substitutedhydrocarbon residue having 1-20 carbon atoms and a substituted ornon-substituted hydrocarbon residue having 1-20 carbon atoms and atleast one heteroatom selected from the group consisting of oxygen,nitrogen and sulfur; R₂ is selected from the group consisting ofhydrogen and an alkyl having 1-10 carbon atoms; and R₃ is selected formthe group consisting of hydrogen, a substituted or non-substitutedhydrocarbon residue having 1-20 carbon atoms and a substituted ornon-substituted alkyl having 1-20 carbon atoms and at least oneheteroatom selected from the group consisting of oxygen, nitrogen andsulfur.

According to still further features in the described preferredembodiments R is a substituted or non-substituted alkyl having 3-5carbon atoms.

According to still further features in the described preferredembodiments the organic acid residue is selected from the groupconsisting of a butyric acid residue, a valeric acid residue, a4-phenylbutyric acid residue, an 4-aminobutyric acid residue, a retinoicacid residue, a sulindac acid residue, an acetyl salicylic acid residue,an ibuprofen residue, a malonic acid residue, a succinic acid residue, aglutaric acid residue, a fumaric acid residue and a phthalic acidresidue.

According to a further aspect of the present invention there is provideda method of synthesizing the chemical conjugates of the presentinvention. The method comprises reacting an organic acid and apsychotropic drug, so as to obtain a residue of the organic acidcovalently linked to a residue of the psychotropic drug.

According to further features in preferred embodiments of the inventiondescribed below, the residue of the organic acid is covalently linked tothe residue of the psychotropic drug via a carboxylic ester bond, andthe method further comprising, prior to the reacting, converting theorganic acid into an acyl chloride derivative thereof.

According to still further features in the described preferredembodiments the residue of the organic acid is covalently linked to theresidue of the psychotropic drug via a thioester bond, and the methodfurther comprising, prior to the reacting, converting the organic acidinto an acyl chloride derivative thereof and converting the psychotropicdrug into a thiol derivative thereof.

According to still further features in the described preferredembodiments the residue of the organic acid is covalently linked to theresidue of the psychotropic drug via an amide bond, and the methodfurther comprising, prior to the reacting, converting the organic acidinto an acyl chloride derivative thereof and converting the psychotropicdrug into an amine derivative thereof.

According to still further features in the described preferredembodiments the residue of the organic acid is covalently linked to theresidue of the psychotropic drug via an alkyloxy carboxylic ester bondand the method further comprising, prior to the reacting, converting thepsychotropic drug into a chloroalkyl ester derivative thereof.

The organic acid and the psychotropic drug used in the method describedabove are preferably derived from the organic acid residue and thepsychotropic drug residue of the present invention, describedhereinabove.

In cases where the organic acid is a GABA agonist that comprises a freeamino group, the method further comprising protecting the free aminogroup with a protecting group, prior to the reacting, so as to obtain bythe reacting an amino-protected residue of the organic acid covalentlylinked to the residue of the psychotropic drug, and removing theprotecting group after obtaining the amino-protected residue of theorganic acid covalently linked to the residue of the psychotropic drug.Preferably, the method further comprises, after the protecting and priorto the reacting, converting the organic acid into an acyl imidazolederivative thereof.

The present invention successfully addresses the shortcomings of thepresently known configurations by providing new and potent chemicalconjugates of psychotropic drugs that induce minimized adverse sideeffects for the treatment and prevention of psychotropic and/orproliferative disorders and diseases and for use as chemosensitizers.

BRIEF DESCRIPTION OF THE DRAWINGS

The file of this patent contains at least one drawing executed in colorphotograph. Copies of this patent with color photograph(s) will beprovided by the Patent and Trademark Office upon request and payment ofnecessary fee.

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

In the drawings:

FIGS. 1 a and 1 b show a bar graph and plots, obtained by StructureActivity Relationship (SAR) studies, demonstrating the effect ofperphenazine and its chemical conjugates according to the presentinvention (AN 167, AN 168 and AN 130) on total catalepsy (FIG. 1 a) andon prolactin blood levels (FIG. 1 b) in rats injected intraperitoneallywith 5 mg/Kg body weight perphenazine and equimolar doses of itschemical conjugates;

FIG. 2 is a bar graph demonstrating the total catalepsy in ratsfollowing treatment with 5 mg/Kg perphenazine and equimolar doses of itschemical conjugates according to the present invention (SAR studies);

FIGS. 3 a and 3 b show a bar graph and plots demonstrating the effect ofperphenazine (5 mg/Kg), fluphenazine (7.5 mg/Kg) and their chemicalconjugates (AN 167, AN 168, AN 180 and AN 187) according to the presentinvention (administered in equimolar doses) on total catalepsy in rats(FIG. 3 a) and the effect of perphenazine, fluphenazine and their GABAchemical conjugates AN 168 and AN 187 on prolactin blood levels in rats(FIG. 3 b);

FIGS. 4 a-b are comparative plots demonstrating the time course ofcatalepsy in rats, induced by perphenazine and its chemical conjugatesaccording to the present invention (FIG. 4 a) and fluphenazine and itschemical conjugates according to the present invention (FIG. 4 b);

FIGS. 5 a and 5 b show a bar graph and comparative plots demonstratingthe effect of a chemical conjugate of perphenazine and GABA (compound AN168) of the present invention and an equimolar dose of a mixture ofperphenazine and GABA on catalepsy in rats;

FIG. 6 is a bar graph demonstrating the effect of the chemicalconjugates AN 167 and AN 168 of the present invention on total catalepsyin rats (averages of four independent experiments);

FIGS. 7 a and 7 b show bar graphs demonstrating the effect of thechemical conjugate AN 168, an equimolar dose of perphenazine and anequidose of a mixture of perphenazine and GABA on catalepsy in mice,measured in terms of the percentage of animals reaching the targetwithin 2 minutes (FIG. 7 a) and in terms of the time it took the animalsto reach the target (FIG. 7 b);

FIGS. 8 a and 8 b present comparative plots demonstrating the effect oforally administered perphenazine and its chemical conjugate AN 168 oncatalepsy in rats, as measured by the “piano” test (FIG. 8 b presentsthe data obtained in experiments conducted 3 months after theexperiments presented in FIG. 8 a);

FIGS. 9 a and 9 b present bar graphs demonstrating the total catalepsyinduced in rats by orally administered perphenazine and its chemicalconjugate AN 168, at various concentrations, as measured by the “piano”test (FIG. 9 b presents the data obtained in experiments conducted 3months after the experiments presented in FIG. 9 a);

FIGS. 10 a and 10 b are comparative plots and a bar graph demonstratingthe effect of various concentrations of orally administered perphenazineand its chemical conjugate AN 168 on the time course of catalepsy (FIG.10 a) and on total catalepsy (FIG. 10 b) in rats, as measured by the“piano” test during 24 hours;

FIG. 11 is a bar graph demonstrating the effect of perphenazine and AN168, orally administered at various concentrations, on total catalepsyin rats, as measured by the “wall” test;

FIG. 12 presents comparative plots demonstrating the effect of orallyadministered perphenazine and AN 168 on prolactin blood levels in rats;

FIG. 13 presents comparative plots demonstrating the effect ofperphenazine and its chemical conjugates of the present invention, AN130, AN 167 and AN 168, on the proliferation of B16 murine melanomacells;

FIG. 14 presents comparative plots demonstrating the effect ofincreasing concentrations of perphenazine, AN 168, GABA, Vincristine andCisplatin on the viability of C6 rat glioma cells;

FIG. 15 presents comparative plots demonstrating the effect ofincreasing concentrations of perphenazine, AN 168 and Dexamethasone onthe viability of Jurkat T lymphoma cells;

FIG. 16 is a bar graph demonstrating the effect of variousconcentrations of perphenazine and AN 168 on the viability of C6 ratglioma cells treated with 30 μM Vincistine;

FIG. 17 is a bar graph demonstrating the effect of Cisplatin (5-50 μM)and a combination of Cisplatin (5-50 μM) and AN 168 (10 and 15 μM) onthe viability of C6 rat glioma cells;

FIG. 18 is a bar graph demonstrating the effect of perphenazine, AN 168and Cisplatin on DNA fragmentation in C6 rat glioma cells;

FIG. 19 is a bar graph demonstrating the effect of perphenazine and itschemical conjugates AN 130, AN 167 and AN 168 on normal brain cells(IC₅₀ values);

FIG. 20 is a bar graph demonstrating the effect of equimolar doses ofperphenazine and AN 168 on the viability of rat myocytic cell;

FIG. 21 presents comparative plots demonstrating the time course ofmortality in rats intraperitoneally injected with perphenazine (per) andcompound AN 167 of the present invention;

FIG. 22 is a bar graph demonstrating the effect of intraperitonealadministration of various concentrations of perphenazine and/or GABA,and of equimolar doses of the chemical conjugate AN-168 onD-amphetamine-induced climbing behavior in rats, by the total number ofclimbing attempts recorded during two hours in each test group (eachpoint represents the Mean+/−SEM, and the number of animal treated);

FIG. 23 presents comparative plots demonstrating the time course of theeffect of intraperitoneal administration of various concentrations ofperphenazine and/or GABA, and of equimolar doses of the chemicalconjugate AN-168 on D-amphetamine-induced climbing behavior in ratsduring two hours;

FIG. 24 is a bar graph demonstrating the effect of intraperitonealadministration of various concentrations of perphenazine and equimolardoses of the chemical conjugate AN-168 on D-amphetamine-induced headmovement in rats, recorded during two hours in each test group (eachpoint represents the Mean+/−SEM, number of animal treated added);

FIG. 25 presents comparative plots demonstrating the time course of theeffect of intraperitoneal administration of various concentrations ofperphenazine and equimolar doses of the chemical conjugate AN-168 onD-amphetamine-induced head movement in rats during two hours;

FIG. 26 is a bar graph demonstrating the effect of oral administrationof 2.5 mg/kg perphenazine, with or without 5 mg/kg GABA, and ofequimolar dose of the chemical conjugate AN-168 on D-amphetamine-inducedclimbing behavior in rats, by the total number of climbing attemptsrecorded in each test group during two hours (each point represents theMean+/−SEM and the number of animal treated);

FIG. 27 is a bar graph demonstrating the effect of oral administrationof 2.5 mg/kg perphenazine with or without 5 mg/kg GABA and of equimolardose of the chemical conjugate AN-168 on D-amphetamine-induced headmovement in rats in each test group during two hours (each pointrepresents the Mean+/−SEM);

FIG. 28 presents comparative plots demonstrating the time course of theeffect of oral administration 2.5 mg/kg perphenazine with or without 5mg/kg GABA and of equimolar dose of the chemical conjugate AN-168 onD-amphetamine-induced head movement in rats during two hours;

FIG. 29 is a bar graph demonstrating the effect of oral administrationof various concentrations of olanzapine on D-amphetamine-inducedclimbing behavior in rats;

FIG. 30 presents comparative plots demonstrating the time course of theeffect of oral administration of various concentrations of olanzapine onD-amphetamine-induced climbing behavior in rats; and

FIG. 31 is a bar graph demonstrating the effect of oral administrationof various concentrations of olanzapine on D-amphetamine-induced headmovement in rats.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of chemical conjugates of psychotropic drugscovalently linked to organic acids, methods of their preparation andtheir use in the treatment of psychotropic disorders and diseases, suchas, but not limited to, schizophrenia, as well as proliferativedisorders and diseases such as, but not limited to, brain tumors, brainmetastases, peripheral tumors, MDR cancer and other proliferativediseases, and as chemosensitizers.

The principles and operation of the chemical conjugates according to thepresent invention may be better understood with reference to thedrawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated by the examples. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

While conceiving the present invention, it was hypothesized that achemical conjugate covalently coupling a psychotropic drug (which mayhave also anti-proliferative and/or chemosensitization activity) and aGABA agonist or an anti-proliferative agent could exert highpsychotropic and/or anti-proliferative therapeutic activity, as well aschemosensitization activity, associated with minimized adverse sideeffects.

The underlying basis for this hypothesis is as follows: psychotropicdisorders and diseases in general and psychotic disorders and diseases,such as schizophrenia, in particular, are treatable by several types ofpsychotropic drugs. However, the administration of the psychotropicdrugs is typically accompanied by short and long term adverse sideeffects such as extrapyramidal symptoms (mainly induced by typicalanti-psychotics) and agranulocytosis (mainly induced by atypicalanti-psychotics). The development of these adverse side effects, inparticular the extrapyramidal symptoms, is attributed to an inducedimbalance in the dopaminergic D1 and D2 receptors and to decreasedactivity of the GABA system in the brain.

Therefore, it was hypothesized that covalently coupling a psychotropicdrug with a GABA agonist would result in a chemical conjugate thatexerts psychotropic activity with minimized side effects.

In particular, it was assumed that such a coupling of a psychotropicdrug and a GABA agonist would be highly beneficial in this respect sinceit would result in a compound that simultaneously exerts a psychotropicactivity and a GABA-increased activity.

An increase of the GABA system activity, which is presently achieved bythe administration of analgesics, GABA agonists or GABA-like compounds,is known to reduce the side effects induced by psychotropic drugs and tofurther provide other therapeutic benefits related to the GABA system(e.g., mood stabilization and relaxation). GABA agonists are furtherknown to antagonize the increased sensitivity of dopaminergic receptorsinduced by psychotropic drugs. However, the administration of certainGABA agonists and analgesics is limited by their hydrophilic nature.

Therefore, it was further hypothesized that a chemical conjugateobtained by covalently coupling a psychotropic drug and a GABA agonistwould be characterized by (i) synergistic psychotropic andGABA-increased activities induced by both the psychotropic drug moietyand the GABA agonist moiety; (ii) reduced psychotropics-induced sideeffects; (iii) improved pharmacokinetics with respect to crossing theblood brain barrier of the coupled psychotropic drug and the GABAagonist as compared to the parent compounds; and (iv) higher affinity todopaminergic receptors in the brain, which would result in improvedpsychotropic activity.

Moreover, it is known in the art that some psychotropic drugs, inparticular neuroleptic drugs such as phenothiazines, are potentanti-proliferative agents and can further serve as chemosensitizers whenused in combination with a chemotherapeutic drug. Therefore it was stillfurther hypothesized that a chemical conjugate covalently coupling apsychotropic drug and a chemical moiety having anti-proliferativeactivity would exert even higher anti-proliferative and/orchemosensitization activity. Such chemical conjugate could be highlybeneficial in the treatment of proliferative disorders and diseases,especially in the brain, due to the affinity of the psychotropicderivative toward brain receptors and its improved brainpharmacokinetics.

While reducing the present invention to practice, as is furtherexemplified in the Examples section that follows, it was found thatcovalently coupling a psychotropic drug and a chemical moiety selectedso as to reduce side effects induced by the psychotropic drug, such as aGABA agonist, or selected so as to exert anti-proliferative activity,results in chemical conjugates that are synergistically characterized by(i) minimized adverse side effects; (ii) high psychotropic activity;(iii) high anti-proliferative activity; (vi) high chemosensitizationactivity; and (iv) reduced toxicity, all as compared to knownpsychotropic drugs. The chemical conjugates that include a GABA agonistwere further characterized by synergistic psychotropic and GABA inducedactivities.

Thus, the chemical conjugates are used according to the presentinvention to treat psychotropic disorders and diseases as well asproliferative disorders and diseases, as anti-proliferative agentsand/or as chemosensitizers. Each of the chemical conjugates which areused to treat psychotropic and/or proliferative disorders and diseasesaccording to the present invention includes a first chemical moiety thatis covalently linked to a second chemical moiety. The first chemicalmoiety is a psychotropic drug residue, whereas the second chemicalmoiety is an organic acid, selected so as to reduce side effects inducedby the psychotropic drug when administered per se and/or to exertanti-proliferative activity.

As used herein, the term “chemical moiety” refers to a residue derivedfrom a chemical compound, which retains its functionality.

The term “residue” refers herein to a major portion of a molecule whichis covalently linked to another molecule, as is well accepted in theart.

Thus, the phrase “psychotropic drug residue” refers to a major portionof a psychotropic drug that is covalently linked to another chemicalmoiety, as this term is defined hereinabove.

As is described hereinabove, the phrase “psychotropic drug” encompassesany agent or drug that exerts an activity in the central nervous systemand thereby can be used in the treatment of various central nervoussystem diseases or disorders.

Hence, psychotropic drug residues, according to the present invention,include, for example, residues derived from anxiolytic drugs such as,but not limited to, benzodiazepines, phenothiazines and butyrophenones,MAO inhibitors, anti-depressants anti-convulsive drugs (also referred toas anti-convulsants), anti-parkinsonian drugs, and acetylcholineesterase inhibitors. The psychotropic drugs can be tricyclic, bicyclicor monocyclic.

According to a preferred embodiment of the present invention, thepsychotropic drug residues are preferably derived from anti-psychoticdrugs, including typical and atypical psychotic drugs.

Particularly preferred psychotropic drugs, according to the presentinvention, are those having an amine group, a thiol group or an hydroxylgroup, as these terms are defined hereinbelow, which can be reacted withthe organic acid or a reactive derivative thereof. Such groups can bepresent in the psychotropic drug either as a free functional group or asa part of another functional group, e.g., an amide group, a carboxylicacid group and the like, as these terms are defined hereinbelow.

Representative examples of residues of such psychotropic drug residues,include, without limitation, a chlorpromazine residue, a perphenazineresidue, a fluphenazine residue, a zuclopenthixol residue, athiopropazate residue, a haloperidol residue, a benperidol residue, abromperidol residue, a droperidol residue, a spiperone residue, apimozide residue, a piperacetazine residue, an amilsulpride residue, asulpiride residue, a clothiapine residue, a ziprasidone residue, aremoxipride residue, a sultopride residue, an alizapride residue, anemonapride residue, a clozapine residue, an olanzapine residue, aziprasidone residue, a sertindole residue, a quetiapine residue, afluoxetine residue, a fluvoxamine residue, a desipramine residue, aparoxetine residue, a sertraline residue, a valproic acid residue atemazepam residue, a flutemazepam residue, a doxefazepam residue, anoxazepam residue, a lorazepam residue, a lormetazepam residue, acinolazepam residue, a flutazolam residue, a lopirazepam residue, ameprobamate residue, a carisoprodol residue, an acetophenazine residue,a carphenazine residue, a dixyrazine residue, a priciazine residue, apipothiazine residue, a homophenazine residue, a perimetazine residue, aperthipentyl residue, a flupentixol residue, a piflutixol residue, ateflutixol residue, an oxypethepin residue, a trifluperidol residue, apenfluridol residue, a meclobemide residue, a norclomipramine residue,an amoxapine residue, a nortriptyline residue, a protriptyline residue,a reboxetine residue, a tacrine residue, a rasagiline residue, anamatadine residue, a phenobarbital residue and a phenytoin residue.

According to a preferred embodiment of the present invention, thepsychotropic drug residue further exerts anti-proliferative activity.Such dual active psychotropic drugs include, for example, phenothiazinesand derivatives thereof.

According to another preferred embodiment of the present invention, thepsychotropic drug residue further exerts chemosensitization activity.Such dual active psychotropic drugs include, for example, phenothiazinesand derivatives thereof, thioxanthenes and derivatives thereof,clozapine, clomipramine and paroxetine.

As used herein, the term “chemosensitization” means an increase or anenhancement of the measured cytotoxicity of a chemotherapeutic agent oncancer cells, particularly multidrug resistant cancer cells, in thepresence of a chemosensitizing agent, as is compared to the level ofcytotoxicity exerted by the chemotherapeutic agent in the absence of thechemosensitizing agent.

The terms “chemosensitizing agent” and “chemosensitizer”, which are usedherein interchangeably, describe compounds that render cancer cells moresensitive to chemotherapy.

As stated hereinabove, the psychotropic drug residue, according to thepresent invention, is covalently coupled to a second chemical moiety,which is an organic acid residue.

The phrase “organic acid residue” refers to a residue, as definedherein, that is derived from an organic acid that includes a freecarboxylic group.

The term “free carboxylic group” includes a “—C(═O)OH” group either asis, in its protonated or in its ionized or salt state.

The organic acid residue, according to the present invention, isselected so as to either reduce the side effects that could be inducedby the psychotropic drug if administered alone or to exertanti-proliferative activity. The organic acid residue, according to thepresent invention, can be, for example, a residue that has a generalformula —R—C(═O)—, where R can be, for example, a hydrocarbon residuethat has 1-20 carbon atoms.

The term “hydrocarbon” as used herein refers to an organic compound thatincludes, as its basic skeleton, a chain of carbon atoms and hydrogenatoms that are covalently linked.

Thus, the hydrocarbon residue according to the present invention can bealkyl or cycloalkyl.

As used herein, the term “alkyl” refers to a saturated aliphatichydrocarbon including straight chain and branched chain groups.Preferably, the alkyl group has 1 to 20 carbon atoms.

Whenever a numerical range, e.g., “1-20”, is stated herein, it meansthat the group, in this case the alkyl group, may contain 1 carbon atom,2 carbon atoms, 3 carbon atoms, etc., up to and including 20 carbonatoms. More preferably, the alkyl is a medium size alkyl having 1 to 10carbon atoms. Most preferably, the alkyl has 3 to 5 carbon atoms.

As used herein, the term “cycloalkyl” includes an all-carbon monocyclicor fused ring (i.e., rings which share an adjacent pair of carbon atoms)group wherein one of more of the rings does not have a completelyconjugated pi-electron system. Examples, without limitation, ofcycloalkyl groups include cyclopropane, cyclobutane, cyclopentane,cyclopentene, cyclohexane, cyclohexadiene, cycloheptane,cycloheptatriene and adamantane.

The hydrocarbon residue, according to the present invention, can bestraight or branched. The hydrocarbon residue can further be saturatedor unsaturated. When unsaturated, the hydrocarbon residue can include adouble bond or a triple bond in its carbon chain. An unsaturatedhydrocarbon residue can further include an aryl.

As used herein, an “aryl” group refers to an all-carbon monocyclic orfused-ring polycyclic (i.e., rings which share adjacent pairs of carbonatoms) groups having a completely conjugated pi-electron system.Examples, without limitation, of aryl groups include phenyl,naphthalenyl and anthracenyl.

The hydrocarbon residue can further be substituted or non-substituted.When substituted, the substituent can be, for example, alkyl,cycloalkyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy,cyano, halo, oxo, amido and amino.

A “heteroaryl” group refers to a monocyclic or fused ring (i.e., ringswhich share an adjacent pair of atoms) group having in the ring(s) oneor more atoms, such as, for example, nitrogen, oxygen and sulfur and, inaddition, having a completely conjugated pi-electron system. Examples,without limitation, of heteroaryl groups, include pyrrole, furane,thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine,quinoline, isoquinoline and purine. The heteroaryl group may besubstituted or non-substituted. When substituted, the substituent groupcan be, for example, alkyl, cycloalkyl, hydroxy, alkoxy, aryloxy, cyano,halo, oxo, amido and amino.

A “heteroalicyclic” group refers to a monocyclic or fused ring grouphaving in the ring(s) one or more atoms such as nitrogen, oxygen andsulfur. The rings may also have one or more double bonds. However, therings do not have a completely conjugated pi-electron system. Theheteroalicyclic may be substituted or non-substituted. When substituted,the substituted group can be, for example, alkyl, cycloalkyl, aryl,heteroaryl, halo, trihalomethyl, hydroxy, alkoxy, aryloxy, cyano, oxo,amido and amino.

A “hydroxy” group refers to an —OH group.

An “alkoxy” group refers to both an —O-alkyl and an —O-cycloalkyl group,as defined herein.

An “aryloxy” group refers to both an —O-aryl and an —O-heteroaryl group,as defined herein.

An “oxo” group refers to a —C(═O)—R′ group, where R′ can be, forexample, alkyl, cycloalkyl or aryl.

A “halo” group refers to fluorine, chlorine, bromine or iodine.

A “trihalomethyl” group refers to a —CX₃— group wherein X is a halogroup as defined herein.

An “amino” or “amine” group refers to a —NH₂ group.

An “amido” or “amide” group refers to a —C(═O)—NR_(a)R_(b) group, whereR_(a) and R_(b) can be, for example, hydrogen, alkyl, cycloalkyl andaryl.

The hydrocarbon residue, according to the present invention, can furtherinclude one or more heteroatoms interspersed within its chain. Theheteroatoms can be, for example, oxygen, nitrogen and/or sulfur.

The hydrocarbon residue can further be a residue that has a generalformula —Z—C(═O)O—CHR₂—R₃, where Z can be, for example, a single bond ora substituted or non-substituted hydrocarbon residue as describedhereinabove; R₂ can be, for example, hydrogen or an alkyl residue having1-10 carbon atoms; and R₃ can be, for example, hydrogen or a hydrocarbonresidue as defined hereinabove.

Thus, representative examples of organic acids from which an organicacid residue according to the present invention can be derived includeoxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid,fumaric acid, phthalic acid, isophthalic acid, tetraphthalic acid,butyric acid, 4-phenylbutyric acid, 4-aminobutyric acid (GABA), valericacid, propionic acid, retinoic acid, acetyl salicylic acid andibuprofen.

According to a presently most preferred embodiment of the presentinvention, the second chemical moiety of the chemical conjugates is aGABA agonist residue.

As used herein, the phrase “GABA agonist residue” refers to a residue,as this term is defined hereinabove, of a GABA agonist, while the term“GABA agonist” describes compounds that are capable of activating theGABA system in the brain and are therefore pharmacologically related toGABA. The term “GABA agonist” is hence understood to include GABAitself, whereas the term “GABA agonist residue” is hence understood toinclude a residue of GABA agonist itself.

Thus, GABA agonist residues, according to the present invention,include, in addition to the GABA (γ-aminobutyric acid) residue itself,residues of other GABA agonist which can be covalently coupled to ananti-psychotic drug.

Examples of such GABA agonists residues include a (±) baclofen residue,an isonipecotic acid residue, a γ-hydroxybutyric acid residue, anaminooxyacetic acid residue, a β-(4-chlorophenyl)-γ-aminobutyric acidresidue, a piperidine-4-sulfonic acid residue, an3-aminopropylphosphonous acid residue, an 3-aminopropylphosphinic acidresidue, an 3-(aminopropyl)methylphosphinic acid residue, a1-(aminomethyl)cyclohexaneacetic acid residue (gabapentin), an4-amino-5-hexenoic acid (y-vinyl GABA, vigabatrin) and an3-(2-imidazolyl)-4-aminobutanoic acid residue.

According to another presently preferred embodiment of the invention,the second chemical moiety in the chemical conjugates of the presentinvention is an anti-proliferative agent residue.

The term “anti-proliferative agent residue”, as used herein, refers to aresidue, as defined herein, of a compound characterized by ananti-proliferative activity.

According to a preferred embodiment of the present invention, theanti-proliferative agent is butyric acid or 4-phenylbutyric acid. Thesecompounds are known to exert anti-cancer activity and are furthercharacterized as compounds of which GABA is a derivative and maytherefore further act as GABA mimetic agents.

According to another preferred embodiment of the present invention, thesecond chemical moiety in the chemical conjugates of the presentinvention is an analgesic.

The incorporation of analgesics in the chemical conjugates of thepresent invention may also provide for dual pharmacological activity,namely, psychotropic activity and pain relief. Furthermore, thepresently known analgesics typically suffer many disadvantages such aspoor pharmacokinetics and adverse side effects, e.g. significantconvulsive effects, oftentimes associated with systemic administrationthereof. Conjugation of analgesics with psychotropic agents cantherefore improve their pharmacokinetics and reduce these side affects.Moreover, it is well accepted in the art that some analgesics areassociated GABA activity.

Thus, the second chemical moiety of the chemical conjugates of thepresent invention include an organic acid residue, which is preferably aGABA agonist residue, an analgesic residue or an anti-proliferativeagent residue, as these terms are defined and exemplified hereinabove.

The second chemical moiety in the chemical conjugates of the presentinvention is covalently linked to the first chemical moiety preferablyvia an ester bond. The ester bond can be a carboxylic ester bond, anoxyalkyl carboxylic ester bond, an amide bond or a thioester bond.

As used herein, the phrase “carboxylic ester bond” includes an“—O—C(═O)—” bond.

As used herein, the phrase “oxyalkyl carboxylic ester bond” includes an“O—R—O—C(═O)—” bond, where R is an alkyl, as defined hereinabove.Preferably R is methyl.

The phrase “amide bond” includes a “—NH—C(═O)—” bond.

The phrase “thioester bond” includes a “—SH—C(═O)—” bond.

Such ester bonds are known to be hydrolizable by brain derived enzymes,such as esterases and amidases, and it is therefore assumed and furtherdemonstrated by the experimental results described herein (see, forexample, FIGS. 5 a-b) that the chemical conjugates of the presentinventions act as prodrugs that are metabolized in the brain and therebysimultaneously release the psychotropic drug and the organic acid, thus,providing for advantageous co-pharmacokinetics for the psychotropic drugand the organic acid.

This process is highly advantageous since it provides (i) a simultaneousaction of the psychotropic drug and the organic acid, whichsynergistically results in reduced side effects induced by the drug andin dual activity of both moieties; (ii) higher affinity of the prodrugto the dopaminergic receptors which results in synergistically higherpsychotropic activity and synergistically higher anti-proliferativeactivity toward brain proliferative disorders; and (iii) improved brainpermeability of both chemical moieties.

In another aspect, the present invention further provides a method ofsynthesizing the chemical conjugates described hereinabove. The methodis effected, generally, by reacting an organic acid with a psychotropicdrug, so as to obtain a residue of the organic acid covalently linked toa residue of the psychotropic drug.

Herein, the terms “a residue of an organic acid” and “a residue of apsychotropic drug” are equivalent to the terms “organic acid residue”and “psychotropic drug residue”, respectively, as these terms aredefined hereinabove. It should be evident to a skilled artisan that byreacting an organic acid and a psychotropic drug, to thereby form acovalent link therebetween, a final product that includes residues ofthe organic acid and the psychotropic drug is produced.

Hence, the organic acid that is reacted in the method of this aspect ofthe present invention, includes any compound that corresponds to theorganic acid residue described hereinabove and can therefore include allthe organic acids from which the organic acid residues describedhereinabove are derived.

For example, organic acids that are usable in the context of this aspectof the present invention include GABA agonists which correspond to thepreferred GABA agonist residues described hereinabove. Similarly, theorganic acids can include anti-proliferating agents, such as butyricacid and 4-phenylbutyric acid, which correspond to theanti-proliferating agent residues described hereinabove.

In the same manner, the psychotropic drug that is reacted in the methodaccording to this aspect of the present invention corresponds to any ofthe psychotropic drug residues described hereinabove.

The method of synthesizing the chemical conjugates of the presentinvention, described hereinabove, can be further manipulated inaccordance with the type of the organic acid used and/or the type of thecovalent linkage between the organic acid residue and the psychotropicdrug residue.

As is discussed in detail hereinabove, preferred organic acids accordingto the present invention include, for example, anti-proliferating agentssuch as butyric acid and derivatives thereof, organic acids that havethe general formula R—C(═O)—OH (corresponding to the organic acidresidue R—(C═O)—O), and others. Most of these preferred organic acids donot include a free amino group and can therefore be used in thesynthesis of the present invention without further manipulations.

As is further discussed in detail hereinabove, in the chemicalconjugates of the present invention, the organic acid residue and thepsychotropic drug residue are covalently linked by an ester bond thatcan be either a carboxylic ester bond, an alkyloxy carboxylic esterbond, a thioester bond or an amide bond, as these terms are definedhereinabove.

In cases where the residues are covalently linked via a carboxylic asterbond, the method of synthesizing the chemical conjugates of the presentinvention is preferably effected by first converting the organic acidinto its corresponding acyl chloride derivative, or any other acylhalide derivative, so as to activate the organic acid. The acyl chloridederivative is thereafter reacted with the psychotropic drug, whichtypically includes a free hydroxyl group, in a well-knownnucleophilic-addition reaction, so as to obtain the desired chemicalconjugate having the organic acid residue covalently linked to thepsychotropic drug residue via a carboxylic ester bond. This reaction ispreferably performed under basic conditions, so as to activate thepsychotropic drug and/or to neutralize compounds that are present astheir hydrochloride salts. However, the organic acid and/or thepsychotropic drug can be activated by any other known method.

In cases where the residues are covalently linked via a thioester bond,the method of synthesizing the chemical conjugates of the presentinvention is preferably effected by converting the psychotropic druginto its corresponding thiol derivative and converting the organic acidinto its corresponding acyl chloride derivative, or into any otheractivated derivative thereof. The thiol derivative is thereafter reactedwith the activated organic acid, by well-known procedures, so as toobtain the desired chemical conjugate having the organic acid residuecovalently linked to the psychotropic drug residue via a thioester bond.It should be noted that some of the presently known psychotropic drugsinclude a free thiol group and therefore such drugs can be directlyreacted with an acyl chloride derivative of the organic acid.Psychotropic drugs that do not include a free thiol group can be easilyreacted so as to obtain a thiol derivative thereof, by methods wellknown in the art.

In cases where the residues are covalently linked via an amide bond, themethod of synthesizing the chemical conjugates of the present inventionis preferably effected by first converting the organic acid into itscorresponding acyl chloride derivative, so as to activate the organicacid and by further converting the psychotropic drug into an aminederivative thereof. The acyl chloride derivative is thereafter reactedwith the amino group of the psychotropic drug, in a well-knownnucleophilic-addition reaction, or by any other of the known proceduresfor producing an amide bond, so as to obtain the desired chemicalconjugate having the organic acid residue covalently linked to thepsychotropic drug residue via an amide bond. It should be noted thatsome of the presently known psychotropic drugs include a free aminegroup and therefore such drugs can be directly reacted with an acylchloride derivative of the organic acid. Psychotropic drugs that do notinclude a free amine group can be easily reacted so as to obtain anamine derivative thereof, by methods well-known in the art.

In cases where the residues are covalently linked via an alkyloxycarboxylic ester bond, the method of synthesizing the chemicalconjugates of the present invention is preferably effected by convertingthe psychotropic drug into a chloroalkyl ester derivative thereof,preferably chloromethyl ester derivative thereof. The chloromethyl esterderivative is thereafter reacted with the organic acid, in a well-knownnucleophilic-addition reaction, or by any other of the known proceduresfor producing an alkyloxy carboxylic ester bond, so as to obtain thedesired chemical conjugate having the organic acid residue covalentlylinked to the psychotropic drug residue via an alkyloxy carboxylic esterbond. It should be noted that covalently linking the organic acid andthe psychotropic drug via an alkyloxy carboxylic ester bond isparticularly preferred in cases where the psychotropic drug includes afree carboxylic acid group, since it avoids the formation of thetypically unstable anhydride conjugate.

The methods described above are typically effective when the organicacid does not have a free amino group. However, in cases where theorganic acid includes a free amino group, as is the case of GABAagonists, for example, the amino group should be protected during thedescribed reaction with psychotropic drug. Protecting the free aminogroup is required since it is a relatively chemically active group,which can therefore undesirably participate in the reaction.

Hence, a preferred method of synthesizing chemical conjugates thatinclude a GABA agonist residue having a free amino group is preferablyeffected by first protecting the free amino group. Protecting the aminogroup can be performed by reacting the organic acid with a knownprotecting group such as, but not limited to, tert-butoxycarbonyl (Boc)and benzyloxycarbonyl (Cbz). The amino-protected organic acid is thenreacted with the anti-psychotic drug, so as to obtain an amino-protectedorganic acid residue covalently linked to the psychotropic drug residue.The protecting group is then removed. Further preferably, theamino-protected organic acid is converted to its acyl imidazolederivative, so as to activate the organic acid prior to the reactionwith the psychotropic drug.

Further according to the present invention there is provided apharmaceutical composition including the chemical conjugate of theinvention as an active ingredient.

As used herein a “pharmaceutical composition” refers to a preparation ofone or more of the chemical conjugates described herein, with otherchemical components such as pharmaceutically suitable carriers andexcipients. The purpose of a pharmaceutical composition is to facilitateadministration of a compound to a subject.

Hereinafter, the term “pharmaceutically acceptable carrier” refers to acarrier or a diluent that does not cause significant irritation to asubject and does not abrogate the biological activity and properties ofthe administered compound. Examples, without limitations, of carriersare propylene glycol, saline, emulsions and mixtures of organic solventswith water.

Herein the term “excipient” refers to an inert substance added to apharmaceutical composition to further facilitate administration of acompound. Examples, without limitation, of excipients include calciumcarbonate, calcium phosphate, various sugars and types of starch,cellulose derivatives, gelatin, vegetable oils and polyethylene glycols.

According to a preferred embodiment of the present invention, thepharmaceutical carrier is an aqueous solution of lactic acid.

In this respect, it should be pointed out that some of the chemicalconjugates of the present invention, according to preferred embodiments,are readily soluble in aqueous media and are therefore easilyformulated. Such convenient formulation provides an additional advantageof the chemical conjugates of the present invention over the known esterconjugates of anti-psychotic drugs, which typically include long-chainfatty acids and are therefore non-soluble in aqueous media andadministered as oily formulation.

Techniques for formulation and administration of drugs may be found in“Remington's Pharmaceutical Sciences,” Mack Publishing Co., Easton, Pa.,latest edition, which is incorporated herein by reference.

Suitable routes of administration may, for example, include oral,rectal, transmucosal, transdermal, intestinal or parenteral delivery,including intramuscular, subcutaneous and intramedullary injections aswell as intrathecal, direct intraventricular, intravenous,intraperitoneal, intranasal, or intraocular injections. Pharmaceuticalcompositions of the present invention may be manufactured by processeswell known in the art, e.g., by means of conventional mixing,dissolving, granulating, dragee-making, levigating, emulsifying,encapsulating, entrapping or lyophilizing processes.

Pharmaceutical compositions for use in accordance with the presentinvention thus may be formulated in conventional manner using one ormore pharmaceutically acceptable carriers comprising excipients andauxiliaries, which facilitate processing of the active compounds intopreparations which can be used pharmaceutically. Proper formulation isdependent upon the route of administration chosen.

For injection, the chemical conjugates of the invention may beformulated in aqueous solutions, preferably in physiologicallycompatible buffers such as Hank's solution, Ringer's solution, orphysiological saline buffer with or without organic solvents such aspropylene glycol, polyethylene glycol. For transmucosal administration,penetrants are used in the formulation. Such penetrants are generallyknown in the art.

For oral administration, the chemical conjugates can be formulatedreadily by combining the active compounds with pharmaceuticallyacceptable carriers well known in the art. Such carriers enable theconjugates of the invention to be formulated as tablets, pills, dragees,capsules, liquids, gels, syrups, slurries, suspensions, and the like,for oral ingestion by a patient. Pharmacological preparations for oraluse can be made using a solid excipient, optionally grinding theresulting mixture, and processing the mixture of granules, after addingsuitable auxiliaries if desired, to obtain tablets or dragee cores.Suitable excipients are, in particular, fillers such as sugars,including lactose, sucrose, mannitol, or sorbitol; cellulosepreparations such as, for example, maize starch, wheat starch, ricestarch, potato starch, gelatin, gum tragacanth, methyl cellulose,hydroxypropylmethyl-cellulose, sodium carbomethylcellulose and/orphysiologically acceptable polymers such as polyvinylpyrrolidone (PVP).If desired, disintegrating agents may be added, such as cross-linkedpolyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such assodium alginate.

Dragee cores are provided with suitable coatings. For this purpose,concentrated sugar solutions may be used which may optionally containgum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethyleneglycol, titanium dioxide, lacquer solutions and suitable organicsolvents or solvent mixtures. Dyestuffs or pigments may be added to thetablets or dragee coatings for identification or to characterizedifferent combinations of active compound doses.

Pharmaceutical compositions, which can be used orally, include push-fitcapsules made of gelatin as well as soft, sealed capsules made ofgelatin and a plasticizer, such as glycerol or sorbitol. The push-fitcapsules may contain the active ingredients in admixture with fillersuch as lactose, binders such as starches, lubricants such as talc ormagnesium stearate and, optionally, stabilizers. In soft capsules, theactive compounds may be dissolved or suspended in suitable liquids, suchas fatty oils, liquid paraffin, or liquid polyethylene glycols. Inaddition, stabilizers may be added. All formulations for oraladministration should be in dosages suitable for the chosen route ofadministration.

For buccal administration, the compositions may take the form of tabletsor lozenges formulated in conventional manner.

For administration by inhalation, the chemical conjugates for useaccording to the present invention are conveniently delivered in theform of an aerosol spray presentation from a pressurized pack or anebulizer with the use of a suitable propellant, e.g.,dichlorodifluoromethane, trichlorofluoromethane,dichloro-tetrafluoroethane or carbon dioxide. In the case of apressurized aerosol, the dosage unit may be determined by providing avalve to deliver a metered amount. Capsules and cartridges of, e.g.,gelatin for use in an inhaler or insufflator may be formulatedcontaining a powder mix of the compound and a suitable powder base suchas lactose or starch.

The chemical conjugates described herein may be formulated forparenteral administration, e.g., by bolus injection or continuousinfusion. Formulations for injection may be presented in unit dosageform, e.g., in ampoules or in multidose containers with optionally, anadded preservative. The compositions may be suspensions, solutions oremulsions in oily or aqueous vehicles, and may contain formulatoryagents such as suspending, stabilizing and/or dispersing agents.

Pharmaceutical compositions for parenteral administration includeaqueous solutions of the active compound in water-soluble form.Additionally, suspensions of the active compounds may be prepared asappropriate oily injection suspensions. Suitable lipophilic solvents orvehicles include fatty oils such as sesame oil, or synthetic fatty acidsesters such as ethyl oleate, triglycerides or liposomes. Aqueousinjection suspensions may contain substances, which increase theviscosity of the suspension, such as sodium carboxymethyl cellulose,sorbitol or dextran. Optionally, the suspension may also containsuitable stabilizers or agents which increase the solubility of theconjugates to allow for the preparation of highly concentratedsolutions.

Alternatively, the active ingredient may be in powder form forconstitution with a suitable vehicle, e.g., sterile, pyrogen-free water,before use.

The chemical conjugates of the present invention may also be formulatedin rectal compositions such as suppositories or retention enemas, using,e.g., conventional suppository bases such as cocoa butter or otherglycerides.

The pharmaceutical compositions herein described may also comprisesuitable solid of gel phase carriers or excipients. Examples of suchcarriers or excipients include, but are not limited to, calciumcarbonate, calcium phosphate, various sugars, starches, cellulosederivatives, gelatin and polymers such as polyethylene glycols.

Pharmaceutical compositions suitable for use in context of the presentinvention include compositions wherein the active ingredients arecontained in an amount effective to achieve the intended purpose. Morespecifically, a therapeutically effective amount means an amount ofchemical conjugate effective to prevent, alleviate or amelioratesymptoms of disease or prolong the survival of the subject beingtreated.

Determination of a therapeutically effective amount is well within thecapability of those skilled in the art, especially in light of thedetailed disclosure provided herein.

For any chemical conjugate used in the methods of the invention, thetherapeutically effective amount or dose can be estimated initially fromactivity assays in cell cultures and/or animals. For example, a dose canbe formulated in animal models to achieve a circulating concentrationrange that includes the IC50 as determined by activity assays (e.g., theconcentration of the test compound, which achieves a half-maximalinhibition of the proliferation activity). Such information can be usedto more accurately determine useful doses in humans.

Toxicity and therapeutic efficacy of the chemical conjugates describedherein can be determined by standard pharmaceutical procedures inexperimental animals, e.g., by determining the IC50 and the LD50 (lethaldose causing death in 50% of the tested animals) for a subject compound.The data obtained from these activity assays and animal studies can beused in formulating a range of dosage for use in human.

The dosage may vary depending upon the dosage form employed and theroute of administration utilized. The exact formulation, route ofadministration and dosage can be chosen by the individual physician inview of the patient's condition. (See e.g., Fingl, et al., 1975, in “ThePharmacological Basis of Therapeutics”, Ch. 1 p. 1).

Dosage amount and interval may be adjusted individually to provideplasma levels of the active moiety which are sufficient to maintain thepsychotropic and/or the anti-proliferative effects, termed the minimaleffective concentration (MEC). The MEC will vary for each preparation,but can be estimated from in vitro and/or in vivo data, e.g., theconcentration necessary to achieve 50-90% inhibition of a proliferationof certain cells may be ascertained using the assays described herein.Dosages necessary to achieve the MEC will depend on individualcharacteristics and route of administration. HPLC assays or bioassayscan be used to determine plasma concentrations.

Dosage intervals can also be determined using the MEC value.Preparations should be administered using a regimen, which maintainsplasma levels above the MEC for 10-90% of the time, preferable between30-90% and most preferably 50-90%.

Depending on the severity and responsiveness of the condition to betreated, dosing can also be a single administration of a slow releasecomposition described hereinabove, with course of treatment lasting fromseveral days to several weeks or until cure is effected or diminution ofthe disease state is achieved.

The amount of a composition to be administered will, of course, bedependent on the subject being treated, the severity of the affliction,the manner of administration, the judgment of the prescribing physician,etc.

Compositions of the present invention may, if desired, be presented in apack or dispenser device, such as a FDA approved kit, which may containone or more unit dosage forms containing the active ingredient. The packmay, for example, comprise metal or plastic foil, such as a blisterpack. The pack or dispenser device may be accompanied by instructionsfor administration. The pack or dispenser may also be accompanied by anotice associated with the container in a form prescribed by agovernmental agency regulating the manufacture, use or sale ofpharmaceuticals, which notice is reflective of approval by the agency ofthe form of the compositions or human or veterinary administration. Suchnotice, for example, may be of labeling approved by the U.S. Food andDrug Administration for prescription drugs or of an approved productinsert. Compositions comprising a chemical conjugate of the inventionformulated in a compatible pharmaceutical carrier may also be prepared,placed in an appropriate container, and labeled for treatment of anindicated condition. Suitable conditions indicated on the label mayinclude, for example, psychotropic disease or disorders such asschizophrenia, paranoia, childhood psychoses, Huntington's disease,Gilles de la Tourette's syndrome, depression, manic depression, anxiety,Parkinson disease, Alzheimer disease and epilepsy, brain proliferativedisorders and MDR cancer, and chemosensitization, as this term isdefined hereinabove.

Hence, according to preferred embodiments of the present invention, thepharmaceutical composition is packaged in a packaging material and isidentified in print, on or in the packaging material, for one or more ofthe following uses: for use in the treatment of psychotropic disordersor diseases, for use in the treatment of brain or peripheralproliferative disorders or diseases, for use in the treatment of cancersuch as MDR cancer and for use in chemosensitization, in combinationwith a chemotherapeutic agent and/or in a medical condition for whichchemosensitization is beneficial.

Further according to the present invention, there is provided a methodfor treating or preventing a psychotropic disorder or disease in asubject (e.g., a human being). The method is effected by administering atherapeutically effective amount of one or more of the chemicalconjugates of the invention to a treated subject.

As used herein, the term “method” refers to manners, means, techniquesand procedures for accomplishing a given task including, but not limitedto, those manners, means, techniques and procedures either known to, orreadily developed from known manners, means, techniques and proceduresby practitioners of the chemical, pharmacological, biological,biochemical and medical arts.

Herein, the term “treating” includes abrogating, substantiallyinhibiting, slowing or reversing the progression of a disease,substantially ameliorating clinical symptoms of a disease orsubstantially preventing the appearance of clinical symptoms of adisease.

As used herein, the phrase “psychotropic disorder or disease” refers toa disorder or disease characterized by an impairment in the centralnervous system. Examples of psychotropic disorders and diseases that aretreatable using the chemical conjugates of the invention, include,without limitation, psychotic disorders or diseases, anxiety disorders,dissociative disorders, personality disorders, mood disorders, affectivedisorders, neurodegenerative diseases or disorders, convulsivedisorders, boarder line disorders and mental diseases or disorders.

Representative examples of such psychotropic disorders or diseasesinclude, without limitation, schizophrenia, paranoia, childhoodpsychoses, Huntington's disease, Gilles de la Tourette's syndrome,depression, manic depression, anxiety, Parkinson disease, Alzheimerdisease and epilepsy.

The term “administering” as used herein refers to a method for bringinga chemical conjugate of the present invention into an area or a site inthe brain that affected by the psychotropic disorder or disease.

The chemical conjugate of the present invention can be administeredintraperitoneally. More preferably, it is administered orally.

The term “subject” refers to animals, typically mammals having a bloodbrain barrier, including human beings.

The term “therapeutically effective amount” refers to that amount of thechemical conjugate being administered which will relieve to some extentone or more of the symptoms of the psychotic disorder or disease beingtreated.

A therapeutically effective amount according to this method of thepresent invention preferably ranges between 0.5 mg/kg body and 50 mg/kgbody, more preferably between 0.5 mg/kg body and 30 mg/kg body, morepreferably between 0.5 mg/kg body and 20 mg/kg body and most preferablybetween 1 mg/kg body and 10 mg/kg body.

The present invention is thus directed to chemical conjugates whichexert psychotropic activity. The chemical conjugates of the presentinvention are highly advantageous since they exert enhanced psychotropicactivity and are further characterized by minimized adverse side effectsinduced thereby.

The term “side effects” as used herein refers to adverse symptoms thatmay develop as a result of administering to a subject a certain drug.Such symptoms may include, for example, extrapyramidal symptoms, as isdetailed hereinabove, and are typically associated with theadministration of psychotropic drugs.

Further according to the present invention, there is provided a methodfor treating or preventing a proliferative disorder or disease in asubject (e.g., a human being). The method is effected by administering atherapeutically effective amount of one or more of the chemicalconjugates of the invention to a treated subject.

As used herein, the term “proliferative disorder or disease” refers to adisorder or disease characterized by cell proliferation. Cellproliferation conditions which may be prevented or treated by thepresent invention include, for example, malignant tumors such as cancerand benign tumors.

As used herein, the term “cancer” refers to various types of malignantneoplasms, most of which can invade surrounding tissues, and maymetastasize to different sites, as defined by Stedman's medicalDictionary 25th edition (Hensyl ed., 1990). Examples of cancers whichmay be treated by the chemical conjugates of the present inventioninclude, but are not limited to, brain and skin cancers. These cancerscan be further broken down. For example, brain cancers includeglioblastoma multiforme, anaplastic astrocytoma, astrocytoma, ependyoma,oligodendroglioma, medulloblastoma, meningioma, sarcoma,hemangioblastoma, and pineal parenchymal. Likewise, skin cancers includemelanoma and Kaposi's sarcoma. Other cancerous diseases treatable usingthe chemical conjugates of the present invention include papilloma,blastoglioma, ovarian cancer, prostate cancer, squamous cell carcinoma,astrocytoma, head cancer, neck cancer, bladder cancer, breast cancer,lung cancer, colorectal cancer, thyroid cancer, pancreatic cancer,gastric cancer, hepatocellular carcinoma, leukemia, lymphoma, Hodgkin'slymphoma and Burkitt's lymphoma.

Other, non-cancerous proliferative disorders are also treatable usingthe chemical conjugates of the present invention. Such non-cancerousproliferative disorders include, for example, stenosis, restenosis,in-stent stenosis, vascular graft restenosis, arthritis, rheumatoidarthritis, diabetic retinopathy, angiogenesis, pulmonary fibrosis,hepatic cirrhosis, atherosclerosis, glomerulonephritis, diabeticnephropathy, thrombic microangiopathy syndromes and transplantrejection.

As is demonstrated in the Examples section that follows, the chemicalconjugates of the present invention exert high and potentanti-proliferative activity on a wide variety of cancer cells, includingMDR cancer cells.

As is further demonstrated in the Examples section that follows, thechemical conjugates of the present invention further exertchemosensitization activity when used in combination with variouschemotherapeutic drugs.

Hence, further according to the present invention there is provided amethod of chemosensitization, as this term is defined hereinabove. Themethod is effected by administering to a subject a therapeuticallyeffective amount of one or more chemotherapeutic agent(s) and achemosensitizing effective amount of the chemical conjugate of thepresent invention.

As used herein, the phrase “chemosensitizing effective amount” describesan amount sufficient for measurable chemosensitization in the presenceof therapeutic amounts of a chemotherapeutic agent.

This method is particularly useful in cases where the subject has MDRcancer such as, but not limited to, leukemia, lymphoma, carcinoma orsarcoma. According to the present invention the chemotherapeutic agentmay be, for example, one of the following: an alkylating agent such as anitrogen mustard, an ethylenimine and a methylmelamine, an alkylsulfonate, a nitrosourea, and a triazene; an antimetabolite such as afolic acid analog, a pyrimidine analog, and a purine analog; a naturalproduct such as a vinca alkaloid, an epipodophyllotoxin, an antibiotic,an enzyme, a taxane, and a biological response modifier; miscellaneousagents such as a platinum coordination complex, an anthracenedione, ananthracycline, a substituted urea, a methyl hydrazine derivative, or anadrenocortical suppressant; or a hormone or an antagonist such as anadrenocorticosteroid, a progestin, an estrogen, an antiestrogen, anandrogen, an antiandrogen, or a gonadotropin-releasing hormone analog.Preferably, the chemotherapeutic agent is a nitrogen mustard, anepipodophyllotoxin, an antibiotic, or a platinum coordination complex. Amore preferred chemotherapeutic agent is Cisplatin or Vincistine.

Thus, the present invention teaches novel chemical conjugates ofpsychotropic drugs, which exert higher psychotropic activity,substantially lower side effects and lower toxicity than thecorresponding non-conjugated psychotropic drugs. These novel conjugatesfurther exert anti-proliferative activity and chemosensitizationactivity and can be therefore beneficially used in the treatment ofproliferative disorders either as prodrugs characterized by reduced sideeffects, low toxicity and high affinity toward brain cells or aschemosensitizers that are used in combination with chemotherapeuticdrugs.

Additional objects, advantages, and novel features of the presentinvention will become apparent to one ordinarily skilled in the art uponexamination of the following examples, which are not intended to belimiting. Additionally, each of the various embodiments and aspects ofthe present invention as delineated hereinabove and as claimed in theclaims section below finds experimental support in the followingexamples.

EXAMPLES

Reference is now made to the following examples, which together with theabove descriptions, illustrate the invention in a non limiting fashion.

Chemical Syntheses and Analyses

Exemplary chemical conjugates of the present invention were synthesizedby reacting the psychotropic agents perphenazine, fluphenazine andvalproic acid with the short-chain fatty acids propionic acid, butyricacid and valeric acid and/or with 4-phenylbutyric acid andγ-aminobutyric acid (GABA). The compounds were prepared in high yieldsand were isolated as crystalline solids, soluble in aqueous 1% lacticacid.

Synthesis of chemical conjugates prepared from perphenazine orfluphenazine and an organic acid—General Procedure: A mixture of theneuroleptic agent perphenazine or fluphenazine (1 equivalent), an acylchloride derivative of a short-chain fatty acid (1.1 equivalents) and,optionally, Et₃N (2 equivalents) (used to free starting materials foundas their HCl salts) in 5-10 ml dimethylformamide (DMF) was stirred atroom temperature, under nitrogen atmosphere, for 24 hours. The mixturewas then partitioned between ethyl acetate and water. The organic layerwas thereafter washed with 5% NaHCO₃ and brine, dried over MgSO₄,filtered and evaporated, to give the desired product.

Synthesis of perphenazine 4-phenylbutyrate (AN 130): Perphenazine and4-phenylbutyryl chloride (the acyl chloride of 4-phenylbutyric acid)were reacted as described above. The obtained crude residue was purifiedby silica gel chromatography, using a mixture of 1:10 methanol:ethylacetate as eluent. The product was obtained as a yellow oil (78% yield).

¹H-NMR (CDCl₃): δ=1.94 (quint, J=6 Hz, 4H, CO₂CH₂CH₂, ArNCH₂CH₂), 2.32(t, J=6 Hz, 2H, CO₂CH₂), 2.64 (m, 12H, six NCH₂), 3.93 (t, J=5.6 Hz, 2H,ArNCH₂), 4.17 (t, J=5.3 Hz, 2H, NCH₂CH₂O), 6.82-7.30 (m, 12H, Ar, Ph)ppm.

¹³C-NMR (CDCl₃): δ=23.25 (CH₂CH₂CO₂), 26.46 (ArNCH₂CH₂), 33.56 (CH₂Ph),35.06 (CH₂CO₂), 45.10 (ArNCH₂), 52.23 (two NCH₂), 52.72 (two NCH₂),55.25 (ArNCH₂CH₂CH₂), 57.04 (NCH₂CH₂O), 61.32 (NCH₂CH₂O), 116.00 (C₁,C₁₀), 122.51 (C₃), 123.15 (C₈), 123.86 (CH₂C(CH)₂), 125.13 (C₂), 126.02(p-Ph), 127.56 (C₉), 127.63 (C₇), 128.01 (o-Ph), 128.41 (m-Ph), 128.49(C₄), 173.33 (CO₂) ppm.

MS (CI, i-Bu): m/z (%)=550 (MH⁺, 1.7).

Synthesis of perphenazine butyrate (AN 167): Perphenazine and butyrylchloride (the acyl chloride of butyric acid) were reacted as describedabove. The product was obtained as a yellow oil (74% yield) and was usedwithout further purification.

¹H-NMR (CDCl₃): δ=0.93 (t, J=7.36 Hz, 3H, Me), 1.63 (sext, J=7.44 Hz,2H, CH₂Me), 1.95 (quint, J=6.7 Hz, 2H, ArNCH₂CH₂), 2.27 (t, J=7.46 Hz,2H, CO₂CH₂), 2.43 (m, 10H, five NCH₂), 2.57 (t, J=5.96 Hz, 2H,NCH₂CH₂O), 3.66 (t, J=5.96 Hz, 2H, ArNCH₂), 4.18 (t, J=5.9 Hz, 2H,NCH₂CH₂O), 6.66 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=13.54 (CH₃CH₂), 18.29 (MeCH₂), 24.06 (ArNCH₂CH₂),36.03 (CH₂CO₂), 45.15 (ArNCH₂), 53.09 (two NCH₂), 53.23 (two NCH₂),55.30 (ArNCH₂CH₂CH₂), 56.51 (NCH₂CH₂O), 61.48 (NCH₂CH₂O), 115.64 (C₁,C₁₀), 122.02 (C₃), 122.69 (C₈), 123.27 (C₅), 124.52 (C₆), 127.23 (C₇),127.29 (C₉), 127.68 (C₄), 133.00 (C₂), 144.32 (C₁₂), 146.29 (C₁₁),173.37 (CO₂) ppm.

MS (CI, NH₃): m/z (%)=473 (M⁺, 100), 474 (MH⁺, 82.64).

Synthesis of perphenazine propionate (AN 177): Perphenazine andpropionyl chloride (the acyl chloride of propionic acid) were reacted asdescribed above. The product was obtained as a yellow oil (85% yield)and was used without further purification.

¹H-NMR (CDCl₃): δ=1.12 (t, J=7.53 Hz, 3H, Me), 1.95 (quint, J=6.8 Hz,2H, ArNCH₂CH₂), 2.32 (q, J=7.57 Hz, 2H, CO₂CH₂), 2.51 (m, 10H, fiveNCH₂), 2.61 (t, J=5.95 Hz, 2H, NCH₂CH₂O), 3.89 (t, J=6.8 Hz, 2H,ArNCH₂), 4.16 (t, J=9.92 Hz, 2H, NCH₂CH₂O), 6.98 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=9.01 (CH₃), 24.08 (ArNCH₂CH₂), 27.44 (CH₂CO₂), 45.18(ArNCH₂), 53.09 (two NCH₂), 53.26 (two NCH₂), 55.32 (ArNCH₂CH₂CH₂),56.50 (NCH₂CH₂O), 61.63 (NCH₂CH₂O), 115.67 (C₁, C₁₀), 122.05 (C₃),122.72 (C₈), 123.30 (C₅), 124.56 (C₆), 127.26 (C₇), 127.33 (C₉), 127.71(C₄), 133.03 (C₂), 144.35 (C₁₂), 146.32 (C₁₁), 174.24 (CO₂) ppm.

MS (CI, NH₃): m/z (%)=459 (MH⁺, 100), 458 (M, 47.63).

Synthesis of perphenazine valerate (AN 178): Perphenazine and valerylchloride (the acyl chloride of valeric acid) were reacted as described.The obtained crude residue was purified by silica gel chromatography,using a mixture of 7:4 ethyl acetate:hexane as eluent. The product wasobtained as a yellowish oil (75% yield).

¹H-NMR (CDCl₃): δ=0.86 (t, J=7.23 Hz, 3H, Me), 1.29 (sext, J=6.97 Hz,2H, CH₂Me), 1.56 (quint, J=7.09 Hz, 2H, CH₂CH₂CO₂), 1.87 (quint, J=6.79Hz, 2H, ArNCH₂CH₂), 2.26 (t, J-7.64 Hz, 2H, CH₂CO₂), 2.37 (m, 10H, fiveNCH₂), 2.54 (t, J=5.93 Hz, 2H, ArNCH₂), 4.14 (t, J=5.95 Hz, 2H,NCH₂CH₂O), 6.53-7.14 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=13.51 (CH₃CH₂), 22.02 (CH₂Me), 23.89 (CH₂CH₂Me),26.82 (ArNCH₂CH₂), 33.80 (CH₂CO₂), 45.07 (ArNCH₂), 53.00 (two NCH₂),53.16 (two NCH₂), 55.09 (ArNCH₂CH₂CH₂), 56.46 (NCH₂CH₂O), 61.42(NCH₂CH₂O), 111.68 (q, J=3.77 Hz, C₁), 115.73 (C₁₀), 118.74 (q, J=3.77Hz, C₃), 122.85 (C₈), 123.77 (C₆), 124.02 (q, J=272 Hz, CF₃), 127.20(C₇), 127.29 (C₉), 127.42 (C₄), 129.34 (q, J=32 Hz, C₂), 129.69 (C₅),144.08 (C₁₁), 145.51 (C₁₂), 173.45 (CO₂) ppm.

MS (CI/NH₃): m/z (%)=522 (MH⁺, 100).

Synthesis of fluphenazine propionate (AN 179): Fluphenazine andpropionyl chloride (the acyl chloride of propionic acid) were reacted asdescribed above. The product was obtained as a yellowish oil (95% yield)and as used without further purification.

¹H-NMR (CDCl₃): δ=1.12 (t, J=7.55 Hz, 3H, Me), 1.91 (quint, J=7.18 Hz,2H, ArNCH₂CH₂), 2.32 (q, J=7.56 Hz, 2H, CO₂CH₂), 2.45 (m, 10H, fiveNCH₂), 2.59 (t, J=5.92 Hz, 2H, NCH₂CH₂O), 3.93 (t, J=7.12 Hz, 2H,ArNCH₂), 4.17 (t, J=5.95 Hz, 2H, NCH₂CH₂O), 6.67-7.14 (m, 7H, Ar).

¹³C-NMR (CDCl₃): δ=8.91 (Me), 23.87 (ArNCH₂CH₂), 27.33 (CH₂CO₂), 45.05(ArNCH₂), 52.98 (two NCH₂), 53.17 (two NCH₂), 55.07 (ArNCH₂CH₂CH₂),56.42 (NCH₂CH₂O), 61.54 (NCH₂CH₂O), 111.65 (q, J=3 Hz, C₁), 115.71(C₁₀), 118.73 (q, J=3.77 Hz, C₃), 122.84 (C₈), 123.73 (C₆), 123.99 (q,J=272 Hz, CF₃), 127.18 (C₇), 127.27 (C₉), 127.41 (C₄), 129.30 (q, J=32Hz, C₂), 129.65 (C₅), 144.05 (C₁₁), 145.48 (C₁₂), 174.10 (CO₂).

MS (CI/NH₃): m/z (%)=494 (MH⁺, 100).

Synthesis of fluphenazine butyrate (AN 180): Fluphenazine and butyrylchloride were reacted as described above. The product was obtained as ayellowish oil (97% yield) and was used without further purification.

¹H-NMR (CDCl₃): δ=0.93 (t, J=7.4 Hz, 3H, Me), 1.32 (sext, J=7.4 Hz, 2H,CH₂Me), 1.92 (quint, J=7.18 Hz, 2H, Ar NCH₂CH₂), 2.27 (t, J=7.4 Hz, 2H,CO₂CH₂), 2.45 (m, 10H, five NCH₂), 2.58 (t, J=5.9 Hz, 2H, NCH₂CH₂O),3.93 (t, J=7.2 Hz, 2H, ArNCH₂), 4.17 (t, J=5.98 Hz, 2H, NCH₂CH₂O),6.67-7.13 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=13.42 (CH₃CH₂), 18.20 (MeCH₂), 23.85 (ArNCH₂CH₂),35.92 (CH₂CO₂), 45.02 (ArNCH₂), 52.97 (two NCH₂), 53.14 (two NCH₂),55.04 (ArNCH₂CH₂CH₂), 56.43 (NCH₂CH₂O), 61.39 (NCH₂CH₂O), 111.62 (q, J=3Hz, C₁), 115.68 (C₁₀), 118.68 (q, J=3.77 Hz, C₃), 122.80 (C₈), 123.70(C₆), 123.98 (q, J=272 Hz, CF₃), 127.15 (C₇), 127.24 (C₉), 127.38 (C₄),129.27 (q, J=32 Hz, C₂), 129.62 (C₅), 144.03 (C₁₁), 145.46 (C₁₂), 173.23(CO₂) ppm.

MS (CI/CH₄): m/z (%)=507.18 (M⁺, 75.3), 508.18 (MH⁺, 57.57), 419.13(M—C₄H₈O₂, 82).

Synthesis of fluphenazine valerate (AN 181): Fluphenazine and valerylchloride (the acyl chloride of valeric acid) were reacted as described.The obtained crude residue was purified by silica gel chromatography,using a mixture of 7:4 ethyl acetate:hexane as eluent. The product wasobtained as a yellowish oil (75% yield).

¹H-NMR (CDCl₃): δ=0.86 (t, J=7.23 Hz, 3H, Me), 1.29 (sext, J=6.97 Hz,2H, CH₂Me), 1.56 (quint, J=7.09 Hz, 2H, CH₂CH₂CO₂), 1.87 (quint, J=6.79Hz, 2H, ArNCH₂CH₂), 2.26 (t, J-7.64 Hz, 2H, CH₂CO₂), 2.37 (m, 10H, fiveNCH₂), 2.54 (t, J=5.93 Hz, 2H, ArNCH₂), 4.14 (t, J=5.95 Hz, 2H,NCH₂CH₂O), 6.53-7.14 (m, 7H, Ar).

¹³C-NMR (CDCl₃): δ=13.51 (Me), 22.02 (CH₂Me), 23.89 (CH₂CH₂Me), 26.82(ArNCH₂CH₂), 33.80 (CH₂CO₂), 45.07 (ArNCH₂), 53.00 (two NCH₂), 53.16(two NCH₂), 55.09 (ArNCH₂CH₂CH₂), 56.46 (NCH₂CH₂O), 61.42 (NCH₂CH₂O),111.68 (q, J=3.77 Hz, C₁), 115.73 (C₁₀), 118.74 (q, J=3.77 Hz, C₃),122.85 (C₈), 123.77 (C₆), 124.02 (q, J=272 Hz, CF₃), 127.20 (C₇), 127.29(C₉), 127.42 (C₄), 129.34 (q, J=32 Hz, C₂), 129.69 (C₅), 144.08 (C₁₁),145.51 (C₁₂), 173.45 (CO₂).

MS (CI/NH₃): m/z (%)=522 (MH⁺, 100).

Synthesis of chemical conjugates prepared form perphenazine orfluphenazine and amino organic acids—general procedure: A mixture of anN-protected amino acid (1 equivalent) and carbonyl diimidazole (CDI)(1.1 equivalents) in 5-10 ml DMF was stirred, under nitrogen atmosphere,for 1 hour. Perphenazine or Fluphenazine (1 equivalent) was addedthereafter and the mixture was stirred under nitrogen atmosphere, at 90°C., for 24 hours. The resulting slurry was evaporated and partitionedbetween ethyl acetate and water. The aqueous phase was extracted twicewith ethyl acetate and the combined organic layer was washed trice withNaHCO₃, twice with brine, dried over MgSO₄, filtered and evaporated. TheN-protected product was obtained as a yellowish oil.

The N-protecting group was removed from the product as follows: To asolution of the N-protected product in ethyl acetate, a solution of 4NHCl in ethyl acetate was added dropwise. The mixture was stirred for 2hours at room temperature. The solvent was thereafter evaporated and theresidue was further dried under high vacuum. The obtained product, as atrihydrochloride salt, was recrystallized from a mixture ofmethanol/ether, filtered and dried.

Synthesis of perphenazine N-boc-4-aminobutyrate: Perphenazine andN-t-boc-GABA (N-t-boc-protected 4-aminobutyric acid) were reacted asdescribed above. The crude product was purified by silica gelchromatography, using a mixture of 20:1 ethyl acetate:ethanol as eluent.The product was obtained as a yellowish oil (63% yield).

¹H-NMR (CDCl₃): δ=1.43 (s, 9H, t-Bu), 1.82 (quint, J=7.18 Hz, 2H,CH₂CH₂NHBoc), 1.90 (quint, J=7.18 Hz, 2H, ArNCH₂CH₂), 2.35 (t, J=8.97Hz, 2H, CO₂CH₂), 2.42 (m, 10H, five NCH₂), 2.60 (t, J=5.98 Hz, 2H,NCH₂CH₂O), 3.16 (q, J=6.85 Hz, 2H, CH₂NHBoc), 3.84 (t, J=7.2 Hz, 2H,ArNCH₂), 4.18 (t, J=5.98 Hz, 2H, NCH₂CH₂O), 5.10 (bs, 1H, NH), 6.83 (m,7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=23.92 (CH₂CH₂NHBoc), 24.98 (ArNCH₂CH₂), 28.21 (t-Bu),39.50 (CH₂CO₂), 45.05 (ArNCH₂), 52.89 (two NCH₂), 53.03 (two NCH₂),55.15 (ArNCH₂CH₂CH₂), 56.34 (NCH₂CH₂O), 60.13 (CH₂NHBoc), 61.29(NCH₂CH₂O), 78.80 (CMe₃), 115.60 (C₁, C₁₀), 121.96 (C₃), 122.65 (C₈),123.22 (C₅), 124.45 (C₆), 127.21 (C₇, C₄), 127.62 (C₉), 132.93 (C₂),144.23 (C₁₂), 146.23 (C₁₁), 155.79 (NCO₂), 172.92 (CO₂) ppm.

Synthesis of Fluphenazine N-boc-4-aminobutyrate: Fluphenazine andN-t-boc-GABA (N-t-boc-protected 4-aminobutyric acid) were reacted asdescribed above. The crude product was purified by silica gelchromatography, using a mixture of 20:1 ethyl acetate:ethanol as eluent.The product was obtained as a yellowish oil (75% yield).

¹H-NMR (CDCl₃): δ=1.49 (s, 9H, t-Bu), 1.77 (quint, J=6.38 Hz, 2H,CH₂CH₂NHBoc), 1.90 (quint, J=6.96 Hz, 2H, ArNCH₂CH₂), 2.35 (t, J=6.38Hz, 2H, CO₂CH₂), 2.45 (m, 10H, five NCH₂), 2.58 (t, J=5.8 Hz, 2H,NCH₂CH₂O), 3.14 (q, J=5.8 Hz, 2H, CH₂NHBoc), 3.94 (t, J=6.38 Hz, 2H,ArNCH₂), 4.2 (t, J=5.8 Hz, 2H, NCH₂CH₂O), 4.92 (bs, 1H, NH), 6.8-7.2 (m,7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=23.88 (CH₂CH₂NHBoc), 25.07 (ArNCH₂CH₂), 28.28 (t-Bu),39.60 (CH₂CO₂), 45.13 (ArNCH₂), 52.94 (two NCH₂), 53.04 (two NCH₂),55.13 (ArNCH₂CH₂CH₂), 56.43 (NCH₂CH₂O), 60.22 (CH₂NHBoc), 61.36(NCH₂CH₂O), 78.92 (CMe₃), 111.77 (q, J=3 Hz, C₁), 115.82 (C₁₀), 118.85(q, J=3.77 Hz, C₃), 122.97 (C₈), 123.91 (C₆), 124.05 (q, J=272 Hz, CF₃),127.30 (C₇), 127.39 (C₉), 127.52 (C₄), 129.42 (q, J=32 Hz, C₂), 129.82(C₅), 144.12 (C₁₁), 145.58 (C₁₂), 155.82 (NCO₂), 173.01 (CO₂) ppm.

Synthesis of perphenazine 4-aminobutyrate trihydrochloride (AN 168):Perphenazine N-boc-4-aminobutyrate, prepared as described above, wasreacted with HCl as described above. The trihydrochloride product wasobtained as a viscous semi-solid oil (quantitative yield).

¹H-NMR (CDCl₃): δ=1.93 (quint, J=7.14 Hz, 2H, CH₂CH₂NH₂), 2.23 (m, 2H,ArNCH₂CH₂), 2.61 (t, J=7.14 Hz, 2H, CO₂CH₂), 3.01 (m, 2H, CH₂NH₂), 3.33(m, 2H, ArNCH₂CH₂CH₂), 3.48-3.87 (m, 10H, five NCH₂), 4.10 (t, J=6.4 Hz,2H, NCH₂CH₂O), 4.48 (m, 2H, ArNCH₂), 7-7.31 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=22.34 (CH₂CH₂NH₂), 22.93 (ArNCH₂CH₂), 31.11 (CH₂CO₂),39.56 (CH₂NH₂), 44.76 (ArNCH₂), 49.42 (two NCH₂), 49.61 (two NCH₂),55.29 (ArCH₂CH₂CH₂), 56.08 (NCH₂CH₂O), 58.64 (NCH₂CH₂O), 116.69 (C₁₀)117.20 (C₁), 123.49 (C₃), 124.19 (C₈), 125.44 (C₅), 126.42 (C₆), 128.20(C₇), 128.56 (C₉), 128.80 (C₄), 134.23 (C₂), 144.97 (C₁₂), 147.37 (C₁₁),173.04 (CO₂) ppm.

MS (CI/CH₄): m/z (%)=403.09 (MH⁺—C₄H₇NO, 100), 489.18 (MH⁺, 1.7).

Synthesis of fluphenazine 4-aminobutyrate trihydrochloride (AN 187):Fluphenazine N-boc-4-aminobutyrate was reacted with HCl, as describedabove. The product was obtained as a white solid (75% yield).

¹H-NMR (CDCl₃): δ=1.93 (quint, J=7.25 Hz, 2H, CH₂CH₂NH₂), 2.29 (quint,J=5.42 Hz, 2H, ArNCH₂CH₂), 2.49 (t, J=7.14 Hz, 2H, CO₂CH₂), 2.99 (t,J=7.54 Hz, 2H, CH₂NH₂), 3.39 (t, J=4.87 Hz, 2H, ArNCH₂CH₂CH₂), 3.40 (t,J=5.42 Hz, 2H, NCH₂CH₂N), 3.4-4.0 (m, 8H, four NCH₂), 3.91 (m, 2H,NCH₂CH₂O), 4.18 (t, J=6.12 Hz, 2H, ArNCH₂), 7.02-7.33 (m, 7H, Ar) ppm.

¹³C-NMR (CDCl₃): δ=22.76 (ArNCH₂CH₂), 23.36 (CH₂CH₂NH₂), 31.49 (CH₂CO₂),39.96 (CH₂NH₂), 45.21 (ArNCH₂), 49.57 (two NCH₂), 50.02 (two NCH₂),55.72 (ArNCH₂CH₂CH₂), 56.48 (NCH₂CH₂O), 58.99 (NCH₂CH₂O), 113.41 (q,J=3.77 Hz, C₁), 117.80 (C₁₀), 120.70 (q, J=3.77 Hz, C₃), 124.89 (C₈),126.24 (C₆), 125.59 (q, J=272 Hz, CF₃), 128.75 (C₇), 128.97 (C₉), 129.25(C₄), 130.96 (q, J=32 Hz, C₂), 132.51 (C₅), 145.12 (C₁₁), 147.25 (C₁₂),173.48 (CO₂) ppm.

MS (CI/CH₄): m/z (%)=523 (MH⁺, 0.5), 280 (M—C₁₄H₉NF₃S, 100).

Synthesis of Chemical Conjugates Prepared from Valproic Acid and OrganicAcids or Amino Organic Acids—General Procedure:

Valproic acid is reacted with chloromethyl chlorosulfate (1.2equivalents), in the presence of NaHCO₃, Bu₄N⁺HSO₄ ⁻, water and CH₂Cl₂at room temperature. The aqueous phase is thereafter separated andwashed with CH₂Cl₂. The organic phase is washed with a saturated aqueoussolution of NaHCO₃, brine, dried (MgSO₄) and is evaporated to give thechloromethyl ester of valproic acid as a residual oil, which is purifiedby distillation. The valproic acid chloromethyl ester is then reactedwith an organic acid or with an N-protected amino organic acid,similarly to the general procedures described above, to thereby yieldthe desired product.

Synthesis of 2-Propyl-pentanoic acid (valproic acid) chloromethyl ester(AN-215): To a mixture of valproic acid (2.76 grams, 19 mmol), NaHCO₃(5.75 grams, 68.4 mmol), Bu₄N⁺HSO₄ ⁻ (0.5 gram), water (25 ml) andCH₂Cl₂ (25 mL), chloromethyl chlorosulfate (3.79 grams, 23 mmol, 1.2equivalents) was added. The mixture was stirred at room temperatureovernight. The aqueous layer was thereafter separated and was washedwith CH₂Cl₂. The organic layer was washed consecutively with a saturatedaqueous solution of NaHCO₃ and brine, dried (MgSO₄) and evaporated, togive a residual oil, which was purified by distillation (b.p. 70° C./4mm Hg), to give 2.05 grams (56% yield) of AN-215.

¹H NMR (CDCl₃): δ=0.92 (t, J=7.3 Hz, 6H, two CH₃), 1.26-1.66 (m, 8H, twoCH₂CH₂), 2.36-2.48 (m, 1H, CH), 5.71 (s, 2H, OCH₂Cl).

¹³C NMR (CDCl₃): δ=13.9 (two CH₃), 20.4 (MeCH₂CH₂), 34.3 (two CH₂CH),45.0 (CH), 68.5 (OCH₂Cl), 174.4 (CO₂).

MS (EI): m/z (%)=193 (MH⁺, 100), 150 (MH⁺—C₃H₇).

Synthesis of 2-Propyl-pentanoic acid (valproic acid)N-boc-4-aminobutyryloxymethyl ester (AN-217): A mixture of N-t-boc-GABA(N-t-boc-protected 4-aminobutyric acid) (1.78 grams, 8.8 mmol) and2-propyl-pentanoic acid chloromethyl ester (1.8 grams, 8.27 mmol) in dryethyl methyl ketone, was stirred under nitrogen atmosphere. Et₃N (1gram, 9.5 mmol) was added dropwise and the reaction mixture was heatedfor 60 hours. The obtained white precipitate was filtered and thefiltrate was evaporated. The residue was dissolved in ethyl acetate,washed consecutively with saturated aqueous NaHCO₃ and brine, dried(MgSO₄), filtered, evaporated and further dried under high vacuum togive the product as an oil (1.7 grams, 57% yield), which was usedsubsequently without further purification.

¹H-NMR (CDCl₃): δ=0.80 (t, J=7.1 Hz, 6H, two CH₃), 1.19-1.72 (s+m, 17H,two CH₂CH₂Me+t-Bu), 1.82 (q, J=7.1 Hz, 2H, CH₂CH₂CH₂), 2.36-2.43 (m, 3H,CH₂CO+CHCO), 3.16 (t, J=6.8 Hz, 2H, NHCH₂), 4.74 (bs, 1H, NH), 5.75 (s,2H, OCH₂O).

¹³C-NMR (CDCl₃): δ=18 (two CH₃), 23 (two MeCH₂), 25 (CH₂CH₂CH₂), 28.2(Me₃C), 31.1 (COCH₂), 34.1 (two CH₂CH), 39.6 (NHCH₂), 44.81 (CH), 79(OCH₂O), 155.8 (NHCO₂), 171.7 (CH₂CO), 175 (CHCO₂).

MS (ES⁺): m/z (%)=382 (M+Na⁺, 65), 360 (MH⁺, 100), 304 (MH⁺—C₄H₈, 98).

Synthesis of 2-Propyl-pentanoic acid (valproic acid)4-aminobutyryloxymethyl ester hydrochloride (AN-216): To a solution of2-propyl-pentanoic acid N-t-boc-4-amino-butyryloxymethyl ester (AN-217,prepared as described hereinabove) (1.7 grams, 4.7 mmol) in ethylacetate, a solution of 4N HCl in ethyl acetate was added. The obtainedmixture was stirred for 4 hours at room temperature, the solvent wasthereafter evaporated and the residue was further dried under highvacuum. The residue was dissolved in ether, and addition of hexane leadto precipitation of the desired product AN-216 (0.75 gram, 62%) as anamorphous solid having a melting point of 35-37° C.

¹H-NMR (CD₃OD): δ=0.9 (t, J=7.1 Hz, 6H, two CH₃), 1.2-1.64 (m, 8H, twoCH₂CH₂Me), 1.95 (q, J=7.5 Hz, 2H, CH₂CH₂CH₂), 2.4-2.5 (m, 1H, CHCO),2.53 (t, J=7.2 Hz, 2H, CH₂CO), 2.99 (t, J=7.2 Hz, 2H, CH₂N), 5.77 (s,2H, OCH₂O).

¹³C-NMR (CD₃OD): δ=14.2 (two CH₃), 21.5 (two MeCH₂), 23.5 (CH₂CH₂CH₂),31.3 (COCH₂), 35.5 (two CH₂CH), 39.9 (NCH₂), 46.2 (CH), 80.6 (OCH₂O),172.5 (CH₂CO), 176.4 (CHCO₂).

MS (CI/NH₃): m/z (%)=260 (MH⁺, 100).

Table 1 below presents the chemical conjugates synthesized by themethods described hereinabove.

TABLE 1 AN-130 Perphenazine 4- Phenylbutyrate C₃₁H₃₆ClN₃O₂S 550.16

AN-167 Perphenazine Butyrate C₂₅H₃₂ClN₃O₂S 474.06

AN-168 Perphenazine 4- aminobutyrate Trihydrochloride C₂₅H₃₃ClN₄O₂S.3HCl598.46

AN-177 Perphenazine Propionate C₂₄H₃₀ClN₃O₂S 460.03

AN-178 Perphenazine Valerate C₂₆H₃₄ClN₃O₂S 488..09

AN-180 Fluphenazine Butyrate C₂₆H₃₂F₃N₃O₂S 507.61

AN-179 (NSK-I- 52) Fluphenazine Propionate C₂₅H₃₀F₃N₃O₂S 493.59

AN-181 (NSK-I- 42) Fluphenazine Valerate C₂₇H₃₄F₃N₃O₂S 521.64

AN-187 fluphenazine 4- Aminobutyrate Trihydrochloride C₂₆H₃₃F₃N₄O₂S.3HCl632.01

AN-216 2-Propyl-pentanoic acid 4- amino-butyryloxymethyl esterhydrochloride

Active Assays Material and Experimental Methods

Cell lines: Human prostate carcinoma (PC-3), human colon carcinoma(HT-29), murine melanoma (B-16) and its drug resistant subclone (B-16MDR), mouse fibroblasts (3T3), myeloid leukemia (HL 60) and its drugresistant subclone (HL 60 MX2), endometrium cell line (MES SA) and itsdrug resistant subclone (MES DX5), jurkat T lymphoma and monocyteleukemia (U-937), were used in this study.

The primary cultures of rat fibroblasts were obtained from neonatal ratsusing known procedures [7].

Neuron cells and glia cells were prepared from pregnant (days 14-15) ICRmice embryo brains. The brains were dissected and homogenized in amixture of Leibowitch L-15 medium (Beth Aemek), 75 μg/ml gentamycin and0.2 mM glutamin. The cells, 300-500 K/well, were seeded inpoly-D-lysine-treated 96 well microplates. The selected neuronal culturewas obtained by adding, 48 hours thereafter, 5-fluorodeoxyuridine (FUDR)and uridine to half of the plates. The untreated cultures included amixture on neuronal and glial cells. The cells were grown in RPMI orDMEM medium supplemented with 10% FCS (fetal calf serum) and with 2 mMglutamine and were incubated at 37° C. in a humidified 5% CO₂ incubator.

Rat myocytes culture was prepared from 1-2 day old Wistar newborn rats(Harlan). Thirty newborn rats were used for obtaining about 25-30million cells. To this end, the hearts were dissected and weretissue-dissociated enzymatically at room temperature using RDB™ (aprotease isolated from fig tree extract). This protocol was repeatedfive times, until the cells were completely dispersed. The dispersedcells were pre-plated in tissue culture flasks, 3×10⁶/ml in DMEM medium,for 45 minutes, and were then transferred to a gelatin coated microtiterplate for 24 hours, in order to reduce non myocytic cells. The cytotoxicagent ARO-C was thereafter added to the culture, to thereby eliminatedividing cells and leave only the undividing myocytes in the culture.The cells were incubated for 4 days and microscopic inspection wasperformed thereafter.

Proliferation of cancer and normal cells: Proliferation was measured byneutral red assay [8] or by a fluorometric assay quantitating DNAcontent [9]. In the neutral red assay, the neutral red is absorbed bylysosomes, thus causing coloring of living cells. Quantitative analysisis performed by colorimetric assay (ELISA reader at 550 nm). In thefluorometric assay, alamar blue is used as a redox indicator. Alamarblue fluorescence was measured at an excitation wavelength of 544 nm andan emission wavelength of 590 mm (FLUOstar BMG Lab Technologies,Offenburg, Germany).

Apoptosis and DNA fragmentation: Fragmentation of cell nuclei wasstudied by flow cytometric analysis of propidium iodide-stained cells.This analysis was performed using a FACScan (Becton Dickinson, MountainView, Calif.) equipped with an argon ion laser adjusted to an excitationwavelength of 480 nm and with a Doublet Discrimination Module (DDM).Lysis II (Becton Dickinson) software was used for data acquisition.Apoptotic nuclear changes were evaluated according to the criteria ofNicolletti et al. [13].

Chemosensitization: The chemosensitizing effect of perphenazine and itschemical conjugate AN 168 was measured in vitro. Various concentrationsof perphenazine or AN 168 were co-administered together with achemotherapeutic agent to either C6 rat glioma cells or to Jurkat Tlymphoma cells. Cells viability and/or DNA fragmentation followingtreatment with either the chemotherapeutic agent, perphenazine, AN 168,a combination of the chemotherapeutic agent and perphenazine or acombination of a chemotherapeutic agent with AN 168 were measured asdescribed hereinabove.

Animals: Young adult male rats (150-230 grams) were purchased fromHarlan (Israel). Animals were divided 2-5/cage and housed in controlledconditions in the animal room for a week prior to the experiments. Theexperiments were conducted with naive animals, in a double blindprocedure. In each experiment various treatment groups (about 5-10animals each) were tested.

Young adult male and female mice were purchased from Harlan, Israel. Theanimals were housed for 4-7 days under controlled conditions prior toexperimentation. Experiments were conducted in a double blind procedure.In each experiment various treatment groups (about 10 animals each) weretested.

Catalepsy in rats: The manifestation of the extrapyramidal adverseeffects induced by typical neuroleptics was evaluated by the appearanceof stereotypic cataleptic behavior in rats following the neuroleptictreatment. Catalepsy was determined by two methods: (i) by measuring thetime it took an animal hanging on a cage wall to move its hind legs andreach a flat surface (the “wall” test); and (ii) rats were placed on aflat surface with their anterior limbs leaning on a flat bar (5.5 cmheight) resembling a piano playing position. Catalepsy was determined bythe time it took an animal to descend and reach the flat surface (the“piano” test). The maximum time of follow up was 2 minutes and thesemeasurements were performed hourly and individually for each animal.These tests provide an assessment of central dopamine (DA) blockingactivity and are acceptable criteria for extrapyramidal symptoms inducedby anti-psychotic drugs [10]. The total induced catalepsy and the timecourse thereof were measured for perphenazine, fluphenazine and forcompounds AN 167, AN 168, AN 177, AN 178, AN 180 and AN 187 (see Table 1hereinabove), comparing different sets of compounds and differentconditions. Generally, 5 mg/Kg of the parent drug perphenazine and 7.5mg/Kg fluphenazine and equimolar doses of their related chemicalconjugates of the present invention, dissolved in 1% lactic acid, wereinjected to the animals intraperitoneally. In a different set ofmeasurements, AN 168 and perphenazine, dissolved in 1% lactic acid, wereorally administered to the animals.

Catalepsy in mice: The appearance of stereotypic cataleptic behavior inmice following the neuroleptic treatment was measured in two differentsets of experiments.

In the first set, adult males were divided into groups and each groupwas treated by either perphenazine (1.5 mg/kg, 9 mice), a mixture ofperphenazine and an equimolar dose of GABA (7 mice), an equimolar doseof AN-168 (8 mice) or by no treatment (control group, 6 mice). Thecatalepsy was determined using a system of two cages and a bartherebetween. The mouse was hung in the middle of the bar, and thepercentage of animals reaching the target within 2 minutes was monitored1 hour, 2 hours and 3 hours following the treatment.

In the second set, young females were divided into groups and each groupwas treated by either 2.5 mg/kg perphenazine (6 mice), a mixture ofperphenazine and an equimolar dose of GABA (6 mice), an equimolar doseof AN-168 (7 mice) or by no treatment (control group, 7 mice). Thecatalepsy was determined using the system described hereinabove. Themouse was hung in the middle of the bar, and the time it took the animalto reach the target was measured.

Prolactin secretion: Typical neuroleptics induce hyperprolactinemia,which is frequently associated with gallactorehea and impaired gonadaland sexual function [11]. The measurement of the circulatory plasmaprolactin level was therefore used as a sensitive biochemical marker forthe psychotropic activity of the known neuroleptics and the chemicalconjugates of the present invention, following intraperitoneal or oraladministration thereof. Thus, blood was collected from the punctured eyeorbital of rats under ether anesthesia and the assay was performed usingMillennia, rat prolactin enzyme immunometric assay-kit (DPC, USA).

Behavioral criteria: Sedation of the animals treated by the chemicalconjugates of the present invention was observed and scored as describedbellow (Table 2). The degree of animal sedation and mobility in thevarious treated groups was evaluated using a score of from 0 to 3, whilea score of 0 represents active and mobile animals, a score of 1represents calm and mobile animals, a score of 2 represents calm andimmobile animals and a score of 3 represents completely ataxic andnon-alert animals. The behavior of the treated animals provided anestimation of the neuroleptic efficacy of the tested known neurolepticsand of the chemical conjugates, as well as the severity of theextrapyramidal symptoms induced thereby.

Toxicity: In vitro toxicity was determined by measuring the effect ofthe tested compounds (either known neuroleptics or the chemicalconjugates of the invention) on primary cultures of neurons and wholebrain neuron and glia cells obtained from the brains of neonatal mice.In vitro toxicity of perphenazine and its chemical conjugate AN 168 wasalso determined with rat myocytes. Acute toxicity in vivo as determinedby the LD₅₀ was evaluated on 2 months old ICR mice following theadministration of a single intraperitoneal bolus-dose of drug.

D-Amphetamine-induced hyperactivity in rats: The efficacy of thechemical conjugates of the present invention was studied using theD-amphetamine-induced hyperactivity and motility model, which is knownas one of the most established animal models for schizophrenia [14].

Naïve Wistar male rats were placed in individual boxes. In eachexperiment 4 rats were studied. Perphenazine or equimolar doses of itschemical conjugate AN-168 were administered intraperitoneally (ip) tothe rats 30 minutes prior to intraperitoneal administration ofamphetamine (2.5 mg/kg), or 90 minutes prior to oral administration ofamphetamine (2.5 mg/kg). The animals locomotor activity was assessedusing two parameters: climbing attempts of the animal on the barrelwalls (as big movements) and head movement of the animal (as smallmovements). Assessment was recorded every 15 minutes for two hours. Eachanimal was tested at each time point for 120 seconds.

Experimental Results

Induced-catalepsy and psychotropic activity of perphenazine and chemicalconjugates containing same: The induced catalepsy and psychotropicactivity of 5 mg/kg perphenazine and equimolar concentrations of itschemical conjugates AN 130, AN 167 and AN 168 (see Table 1 hereinabove)was measured by intraperitoneally injecting the compounds, dissolved in1% lactic acid, to young adult Wistar male rats (weighing 150-200grams), divided 5 per cage and was determined by the “wall” testdescribed hereinabove. A control animals group was treated with thevehicle (lactic acid) only. The effects of the treatment on bothcatalepsy and prolactin secretion were followed for a period of 2 hoursand the results are presented in FIGS. 1 a and 1 b.

FIG. 1 a shows the data obtained for induced catalepsy as the sum of 3determinations that were carried out in duplicates at 0, 60 and 120minutes after the treatment. Each column depicts averages of 5 animals.The total time was normalized to perphenazine (e.g., 100%). The obtaineddata show that catalepsy was induced by the treatment of perphenazineand AN 130 while AN 167 and AN 168 did not induce catalepsy at all.

FIG. 1 b shows the prolactin blood level measured at 0, 60 and 120minutes after the treatment and represents the sum of threedeterminations at each time reference. The prolactin blood level servesas a biochemical marker for the psychotropic activity of the compounds.The obtained data show similar profiles of the prolactin blood level inthe animals when treated with perphenazine, AN 130, AN 167 or AN 168,which peaked at 60 minutes and decreased thereafter. The prolactin bloodlevels, at each time point, in the animals treated with the chemicalconjugates AN 130, AN 167 and AN 168 was similar to that ofperphenazine, indicating that the psychotropic activity of the chemicalconjugates is similar to that of the parent drug. In the controlanimals, treated with the vehicle (1% lactic acid) only, the level ofprolactin was unchanged.

SAR (Structure Activity Relationship) studies: SAR studies wereperformed for perphenazine and the chemical conjugates including same.The induced catalepsy was measured as described hereinabove and wasdetermined by the “wall” test. The results are presented in FIG. 2. Theconjugate of perphenazine and GABA, AN 168, was found to be the mosteffective, resulting with almost maximal reduction of induced catalepsy,followed by the valerate containing conjugate AN178, the propionatecontaining conjugate AN177 and the butyrate containing conjugate AN167.This experiment shows a significant reduction of the induced catalepsyfollowing treatment with the chemical conjugates as compared with thecatalepsy induced by treatment with perphenazine per se.

Catalepsy and animal behavior induced by perphenazine, fluphenazine andchemical conjugates containing same: Perphenazine, fluphenazine and thebutyric acid- and GABA-containing chemical conjugates thereof (AN 167,AN 168, AN 180 and AN 187, see Table 1) were tested for the totalcatalepsy induced thereby, the time course of the induced catalepsy andanimal behavior following the administration thereof. The measurementswere performed following intraperitoneal injections of 5 mg/Kgperphenazine, equimolar concentrations of AN 167 and AN 168, 7.5 mg/Kgfluphenazine and equimolar concentrations of AN 180 and AN 187. Thecatalepsy was determined by the “wall” test.

FIG. 3 a demonstrates the total catalepsy induced by the testedcompounds. The obtained data is a sum of determinations taken at 0, 30,60, 90, 120, 180, 240 and 420 minutes following administration, withtotal time normalization to perphenazine and fluphenazine (=100%). Boththe butyric acid containing chemical conjugates, AN 167 and AN 180,reduced catalepsy significantly. The GABA containing conjugates ofperphenazine, AN168, abolished it, while the GABA conjugate offluphenazine, AN187, reduced it considerably.

FIG. 3 b shows the prolactin blood level measured at 0, 60 and 120minutes after treatment with perphenazine, its GABA conjugate AN 168,fluphenazine and its GABA conjugate AN 187. The obtained data showsimilar profiles of the prolactin blood level in the animals whentreated with perphenazine, fluphenazine or with their GABA chemicalconjugates, which peaked at 60 minutes and decreased thereafter. Theprolactin blood levels, at each time point, in the animals treated withAN 168 and AN 187 were similar to those of perphenazine andfluphenazine, respectively.

FIG. 4 a demonstrates the time course of the catalepsy induced byperphenazine and the chemical conjugates containing same, over a periodof 7 hours. Catalepsy induced by perphenazine peaked after 2 hours anddeclined thereafter. The butyric acid-containing conjugate AN 167induced reduced catalepsy as compared with perphenazine while theanimals treated with the GABA-containing conjugate AN 168 had nocatalepsy through the entire 7 hours period of the study.

FIG. 4 b demonstrates the time course of the catalepsy induced byfluphenazine and the chemical conjugates containing same, over a periodof 7 hours. The animals treated with fluphenazine displayed catalepsyduring the measured 7 hours while those treated with AN 180 and AN 187showed lower catalepsy. The catalepsy induced by AN 180 fluctuatedduring the measurement time while the catalepsy induced by AN 187 wasabolished at the end of the 7-hours period. None of the animals in thestudy had catalepsy after 24 hours.

The effect of the administration of the tested compound on animalsbehavior was measured by evaluating the degree of animal sedation andmobility following the treatment described hereinabove, using a score offrom 0 to 3. A score of 0 represents active and mobile animals, 1represents calm and mobile animals, 2 represents calm and immobileanimals and 3 represents completely ataxic and non-alert animals. Thescores obtained are summarized in Table 2 below and demonstrate thereduced effect of the chemical conjugates on animal behavior as iscompared with that of the known drugs.

TABLE 2 30 min 60 min 90 min 120 min 180 min 240 min Perphenazine 1 2 23 2 2 AN-167 0 1 1 2 2 2 AN-168 0 0 1 1 1 1 Fluphenazine 1 2 3 3 2 2AN-180 1 2 3 2 1 1 AN-187 1 2 2 2 1 1

Induced-catalepsy in rats by AN 168 and a mixture of perphenazine andGABA: The effect of AN 168, the GABA conjugate of perphenazine, on thecatalepsy induced in rats was compared with the catalepsy induced by amixture of its parent drugs—non-conjugated perphenazine and GABA. Thecatalepsy was measured at 60, 90 and 120 minutes following anintraperitoneal injection of the conjugate or the described mixture andwas determined by the “wall” test.

FIG. 5 a shows the data obtained for the total catalepsy induced by thevarious treatments. The animals in the group treated with AN 168exhibited very low catalepsy while the catalepsy in the group treatedwith the mixture of perphenazine and GABA was high.

FIG. 5 b shows the time course of catalepsy following both treatmentsand demonstrates reduced catalepsy in animals treated with AN 168, whichis abolished after 120 minutes.

Catalepsy induced in rats by AN 167 and AN 168: The total catalepsyinduced by AN 167 and AN 168 in four independent experiments was testedand compared with perphenazine-induced catalepsy under the sameexperimental conditions.

The average of total catalepsy following equimolar doses of AN 167 andAN 168, as percentage of the perphenazine-induced catalepsy, is shown inFIG. 6. Although AN 167 induced lower catalepsy as compared withperphenazine, AN 168 reduced the induced catalepsy to almost a zerovalue.

Induced-catalepsy in mice by perphenazine, a mixture of perphenazine andGABA and by AN 168: The effect of AN 168, the GABA conjugate ofperphenazine, on the catalepsy induced in mice was compared with thecatalepsy induced by perphenazine alone and by a mixture of the parentdrugs—non-conjugated perphenazine and GABA. The catalepsy was measuredat 60, 90 and 120 minutes following an intraperitoneal injection of thetreatment, and was determined as described hereinabove.

FIG. 7 a shows the data obtained for the catalepsy induced by thevarious treatments in terms of percentage of animals reaching thetargets within 2 minutes. The animals in the group treated with AN 168exhibited substantially lower disability while the animals in the groupstreated with perphenazine alone and with a mixture of perphenazine andGABA exhibited higher catalepsy.

FIG. 7 b shows the data obtained for the catalepsy induced by thevarious treatments, 2 and 3 hours following the above treatments, interms of the time it took the animals to reach the target. The animalsin the group treated with AN 168 were much faster than the animalstreated with perphenazine alone and with a mixture of perphenazine andGABA.

Induced-catalepsy, induced animal behavior and psychotropic activity oforally administered perphenazine and its GABA conjugate AN 168: As AN168, the chemical conjugate of perphenazine and GABA was found to be thepresently most effective chemical conjugate when administeredintraperitoneally, additional comparative experiments were performed inorder to determine the oral efficacy of this chemical conjugate ascompared with perphenazine. To this end, the induced catalepsy, theprolactin blood levels and the animal behavior were measured asdescribed hereinabove, following oral administration of either AN 168 orperphenazine alone to rats. Animals, divided 5 per cage, were treated byoral administration of perphenazine or AN-168 dissolved in 1% lacticacid. Control animals received vehicle (lactic acid) only.

The catalepsy induced by oral administration of various concentrationsof AN 168 and perphenazine was measured by the “wall” test and the“piano” test described hereinabove. The time course of catalepsy wasmeasured 4-24 hours following oral administration of 2.5, 5, 10 and 20mg/kg perphenazine and respective equimolar doses of 3.5, 7, 14 and 28mg/kg AN-168. The total catalepsy represents the sum of averagecatalepsy per treated group during the 4-24 hours of follow-up.

FIG. 8 a shows the time course of catalepsy following the varioustreatments, as measured by the “piano” test during 4-6 hours, anddemonstrates the consistent reduction in the cataleptic behavior at allconcentrations of AN 168. Statistical analysis indicated that thereduction was more significant (p<0.05) at the low and intermediatedoses of AN 168 (7 and 14 mg/kg) as compared to their respectiveequimolar doses of perphenazine. At higher doses of the chemicalconjugate (14 and 28 mg/kg) the detected cataleptic symptoms wereconsistently lower than those of perphenazine although the differenceswere less substantial. It is assumed though that these smallerdifferences between the catalepsy induced by the drug and the chemicalconjugate at the higher doses result from the assessment procedure. Dueto practical considerations, the maximal cataleptic signal measured waslimited to 120 seconds. However, in reality, it is estimated that themaximum cataleptic signal induced by perphenazine is higher than the oneelicited by the chemical conjugate. This estimation is further supportedby the greater and substantial differences between AN-168 andperphenazine that were observed, at high doses, for both the catalepsydetermined by the “wall” test and the sedation score, which aredescribed hereinafter. Moreover, the experiments conducted showed thatmuscular rigidity and tachypnea were observed only in the animalstreated with the intermediate and high doses of perphenazine (10 and 20mg/kg) and not in the animals treated with the respective equimolardoses of the chemical conjugate.

FIG. 8 b shows the time course of catalepsy following the varioustreatments, as measured by the “piano” test during 4-6 hours, inseparate experiments conducted 3 months after the experiments presentedin FIG. 8 a. The obtained data indicate that at high doses of AN 168 (14and 28 mg/kg), higher catalepsy was induces as compared with theproceeding experiments. NMR spectroscopy revealed that slowdecomposition, probably due to hydrolysis, occurred and therefore theunique properties of the chemical conjugate were affected. Thesefindings suggest that this compound should be stored in sealed vials andexposed only prior to use. It should be noted in this respect that theanalogous chemical conjugate of fluphenazine, AN 187, does not appear tobe hygroscopic and therefore does not tend to decompose upon a prolongedstorage.

FIGS. 9 a and 9 b show the total catalepsy induced by the oraladministration of 5, 10 and 20 mg/kg perphenazine and respectiveequimolar doses of 7, 14 and 28 mg/kg AN-168, observed during 4-6 hours.FIG. 9 b presents the data obtained in experiments conducted 3 monthsafter the experiments presented in FIG. 9 a. Although the reduction inthe cataleptic behavior induced by AN 168 as compared with perphenazineis less significant in the data presented in FIG. 9 b, it is clearlyshown that the catalepsy induced by AN 168 is consistently lower thanthat induced by perphenazine.

FIGS. 10 a and 10 b show the time course of catalepsy (FIG. 10 a) andthe total catalepsy (FIG. 10 b) as measured by the “piano” test during24 hours following the various treatments. The data obtained demonstratethat the maximal cataleptic effect of both perphenazine and AN-168 wasachieved 5-6 hours following treatment and that 24 hours post-treatmentthe catalepsy was reduced in all treatment groups. These data are inline with the clinical time course observed for perphenazineadministered to patients (once daily).

FIG. 11 shows the total catalepsy following the various treatments, asmeasured by the “wall” test and clearly demonstrates that the catalepticsymptoms were almost abolished following treatment with all the testeddoses of AN 168.

The effect of the oral administration of the chemical conjugate AN 168on animals behavior was measured by evaluating the degree of animalsedation and mobility, 4-6 hours following oral treatments with variousconcentrations of AN 168 and perphenazine, using a score of from 0 to 3,as is described hereinabove. The scores obtained are summarized in Table3 below and demonstrate the reduced effect of the chemical conjugate onanimal behavior as compared with perphenazine.

TABLE 3 Treatment Dose (mg/kg) Sedation score perphenazine 20 3perphenazine 10 2 perphenazine 5 1 perphenazine 2.5 0 AN 168 28 2 AN 16814 1 AN 168 7 0 AN 168 3.5 0 control 0

As a marker for the dopaminergic activity of the orally administeredcompounds, the prolactin blood levels were measured 0, 90 and 180minutes following the various treatments described hereinabove. Theobtained data is summarized in FIG. 12 and demonstrate the similarprofiles of the prolactin blood level in the animals treated withperphenazine and AN 168. The prolactin blood levels, at each time point,in the animals treated with AN 168 were similar to those ofperphenazine, at low and intermediate doses, while at a higher dose theprolactin blood level in the animals treated with AN 168 was much higheras compared with animals treated with perphenazine.

These results demonstrate that AN 168 is highly efficient, and thereforerelevant to clinical use, at low doses (e.g., 3.5 and 7 mg/kg), whenorally administered. It is further shown herein that at these low doses,AN 168 caused minimal extrapyramidal symptoms, and is therefore almostdevoid of antagonistic activity at the nigro-striatal pathway.

Anti-proliferative activity: The anti-proliferative activity ofperphenazine, the chemical conjugates thereof AN 167, AN 168 AND an 177,fluphenazine, the chemical conjugates thereof AN 179, AN 180, AN 181 andAN 187, and of butyric acid (BA), 4-phenylbutyric acid (PBA) and GABAwas measured by proliferation tests performed (usually in more than oneindependent experiment) with normal and transformed cells. The cellswere sub-cultured and the tested compounds were added thereto inincreasing concentrations. The IC₅₀ values were determined by linearregression of the survival percentage of the cells. The IC₅₀ valuesobtained for the tested compounds with the various tested cell lines aresummarized in Table 4 and Table 5 below.

TABLE 4 Cells B16 Normal rat Drugs MDR B16 HT-29 PC-3 3T3 fibroblastsPerphenazine 18.45 ± 5.4  12.5 ± 1.29 8.85 ± 2.7 23.1 ± 2.3  26.6  n =3* n = 4 n = 4 n = 2 BA 8000 ± 546 1300 ± 113   7170 ± 2034 5540 n = 3 n= 3 n = 4 GABA >20000 >20000 >20000 >20000 n = 3 n = 3 n = 3 AN-167 41.5± 1.8 17.3 ± 4.5  13.3 ± 2.4 49.1 21.7 31.64 n = 3 n = 5 n = 4 AN-168 23 ± 16 26.8 ± 1.8  23.1 ± 9   45.5 25 45.8 n = 3 n = 3 n = 3 AN-130  58 36.5 ± 8.1  17.27 ± 3.07 52.9 ± 28.7 41.9 ± 16.8 n = 5 n = 5 n = 3n = 2 AN-177 25.8 24.6 AN-178 11.5 18.6 *Number of independentexperiments.

TABLE 5 Cells HL 60 MES SA MX2 MES DX5 Drugs HL 60 (MDR) SA (MDR) JURKATU-937 Perphenazine 19.76 22.55 15.31 16.24 11.34 21.30 AN 167 17.2919.86 17.23 20.90 11.40 23.28 AN 168 15.14 18.36 18.20 17.16 11.35 14.23AN 177 15.13 17.59 Fluphenazine 20.94 21.77 14.79 13.74 14.30 21.51 AN179 18.25 21.42 AN 180 19.00 18.76 11.96 12.74 10.43 12.25 AN 181 14.7916.69 AN-187 18.57 17.10 14.37 9.47 10.31 18.86

These results show that although GABA, by itself, fails to demonstrate asignificant anti-proliferative activity (IC₅₀>20 mM), and BA (IC₅₀ rangeof 1-8 mM) and PBA (IC₅₀ range of 2-12 mM, data not shown) showednoticeable yet relatively low anti-proliferative activity, theirrespective perphenazine and fluphenazine conjugates had significantlyhigher activity (IC₅₀ range of 8-60 μM).

These results further demonstrate the versatile anti-proliferativeactivity of the chemical conjugates of the present invention in a widevariety of cell lines, including multidrug resistant (MDR) cells, suchas HL 60 MX2, B16 MDR subcolon and MES SA DX5.

FIG. 13 shows the results obtained in a representative experiment wherethe effect of perphenazine and the chemical conjugates thereof on theproliferation of B16 murine melanoma cells was measured. AN 167 and AN168 were found to be relatively active as anti-proliferative drugs.

The cytotoxic effect of perphenazine, GABA and the chemical conjugatethereof AN 168, were measured and compared with the cytotoxic effect ofthe known chemotherapeutic drugs Cisplatin and Vincistine, on C6 ratglioma cells. The cells were sub-cultured and the tested compounds wereadded thereto in increasing concentrations, up to 100 μM. The cellsviability following these treatments (24 hours) was determined by theneutral red method described hereinabove and the results are presentedin FIG. 14. The IC₅₀ values of perphenazine and AN 168 were determinedas described hereinabove, and were found to be 19.2 μM and 24.2 μM,respectively.

As is shown in FIG. 14, the obtained data demonstrates the superioranti-proliferative activity of the chemical conjugates of the presentinvention, as compared with representative known chemotherapeutic drugs.C6 glioma cells are known as MDR cells, and indeed, theanti-proliferative activity of the known chemotherapeutic drugs wasfound to be substantially low. In contrast, AN 168 was found to exerthigh anti-proliferative activity, causing substantial cell death atrelatively low concentrations (about 20 μM).

FIG. 15 presents the data obtained following treatment of Jurkat Tlymphoma cells with increasing concentrations of perphenazine, AN 168and Dexamethasone. The results are presented in terms of cellsviability, determined by the alamar blue method, and demonstrate thesuperior cytotoxic effect of AN 168 and perphenazine, as compared withDexamethasone. The IC₅₀ values of perphenazine and AN 168 were 16 μM and19 μM, respectively.

It should be further noted that although perphenazine, fluphenazine andtheir chemical conjugates exert anti-proliferative activity to about thesame extent, the clinical use of the chemical conjugates of the presentinvention is highly superior over the clinical use of the neurolepticdrugs, as the administration of the chemical conjugates is almostcompletely devoid of adverse side effects.

Chemosensitizing effect by co-administration of perphenazine or AN 168and chemotherapeutic drugs: The chemosensitizing effects of 5, 10 and 15μM perphenazine and equimolar doses of its chemical conjugate AN 168were measured by co-administering these compounds with varyingconcentrations of known chemotherapeutic drugs such as Vincistine,Cisplatin and Dexamethasone. The cells viability and/or the DNAfragmentation, determined as described hereinabove in the methodssection, following these combined treatments was compared with theresults obtained following treatments with the chemotherapeutic drugalone.

FIG. 16 presents the data obtained following 24 hours treatment of ratC6 glioma cell line (MDR cells) with Vincistine (30 μM), perphenazine,AN 168 and combinations thereof. The results clearly demonstrate thechemosensitizing effect of AN 168, which, when co-administered with thechemotherapeutic drug, substantially enhance the cytotoxic effectthereof, even at low concentrations of the chemical conjugate (e.g., 5μM), as compared with the cytotoxic activity of the drug whenadministered alone.

FIG. 17 presents the data obtained following treatment of rat C6 gliomacell line (MDR cells) with Cisplatin at various concentrations rangingbetween 5 μM and 50 μM, and with a combination of Cisplatin and 10 and15 μM of AN 168. The results are presented in terms of cells viability,measured by the neutral red method, and clearly demonstrate that whilethe cells were completely resistant to Cisplatin at all the testedconcentrations, the combined treatment of Cisplatin and AN 168 renderedthe cells susceptible to the chemotherapeutic drug.

FIG. 18 presents the DNA fragmentation data obtained following treatmentof rat C6 glioma cells with Cisplatin (30 μM), perphenazine (25 and 50μM), AN 168 (25, 50 μM), a combination of Cisplatin (30 μM) and AN 168(50 μM), compared with untreated cells. The DNA fragmentation wasdetermined by the propidium iodide flow cytometric method describedhereinabove. The results demonstrate that while Cisplatin alone has noeffect of DNA fragmentation, perphenazine and AN 168 both induced adramatically increase in DNA fragmentation. These results suggest thatthe chemosensitizing effect of the chemical conjugates of the presentinvention results from this activity thereof.

Toxicity: The in vitro toxicity of perphenazine, AN 167 and AN 168 wasmeasured on primary cultures of neuronal cells and a mixture of neuronaland glial cells, obtained from neonatal mouse brains. The cell cultureswere treated with the tested compounds for 24 hours and their viabilitywas determined thereafter by the neutral red colorimetric test. The IC₅₀values obtained in these tests demonstrate that perphenazine and AN 167had similar toxicity while AN 168 exhibited significantly lower toxicitytoward normal brain cells, as shown in FIG. 19. The in vitro toxicity ofperphenazine and AN 168 was further measured on cultured rat myocytes.FIG. 20 presents the cells viability, determined as describedhereinabove, following treatment with various concentrations ofperphenazine or AN 168. The obtained data show that AN 168 did not causeany decrease in cells viability at all concentrations, whileperphenazine caused a 20% decrease in cells viability at highconcentrations.

The in vivo toxicity of perphenazine and AN 167 was evaluated followingthe intraperitoneal administration of a single dose thereof to mice. TheLD₅₀ values, determined two weeks following the treatment, were 109mg/kg for perphenazine and 120 mg/kg for AN 167. In addition to thelower toxicity of AN 167 compared with perphenazine (per), the mortalitycaused by the conjugated compound was delayed, as shown in FIG. 21.

D-Amphetamine-induced hyperactivity in rats: The efficacy of thechemical conjugates of the present invention was studied using theD-amphetamine-induced hyperactivity and motility model. This model hasthe advantage of being a predictive and reproducible model for theselection of compounds that have anti-psychotic activity inamphetamine-associated disorders such as schizophrenia[14]. Using thismodel, the efficacy of a chemical conjugate of perphenazine and GABA,AN-168, was studied and compared with that of the parent compounds,perphenazine and GABA, administered alone.

Thus, naïve Wistar male rats were divided into several groups, eachgroup was treated, 90 minutes prior to intraperitoneal administration of2.5 mg/kg amphetamine, by intraperitoneal administration of a certainconcentration of perphenazine (0.5, 1.5 or 3 mg/kg) a certainconcentration of AN-168 (0.5 or 1.5 mg/kg), of 5 mg/kg GABA or of 1.5mg/kg perphenazine and 5 mg/kg GABA. The climbing behavior of the ratsin each group was measured as described hereinabove.

As is shown in FIGS. 22 and 23, AN-168 completely antagonized theclimbing behavior induced by amphetamine even at low doses, therebydemonstrating its high and superior psychotropic efficacy, as comparedwith its parent drugs perphenazine and GABA.

However, as is shown in FIGS. 24 and 25, the effect of AN-168 inreducing head movements and other small body movement was inferior tothat of perphenazine. It is believed that this inferiority results fromthe reduced extrapyramidal side effects, namely cataleptic symptoms andsedation, induced by the conjugate AN-168, as compared with the parentperphenazine. As is further shown in FIGS. 22-25, the administration ofGABA alone did not modify the effect of amphetamine, neither it changedthe effect of perphenazine, thereby suggesting that the enhancedefficacy and the reduced adverse side effects results from theadministration of the conjugate AN-168.

As is shown in FIGS. 26-28, similar results were obtained when 2.5 mg/kgperphenazine, alone or in combination with 5 mg/kg GABA, and 3.5 mg/kgAN-168 were orally administered to rats, 90 minutes prior tointraperitoneal administration of amphetamine, demonstrating thesuperior efficacy of the conjugate in versatile administration routes.

The efficacy of AN-168 was further compared with that of olanzapine, aknown atypical anti-psychotic drug. Various concentrations of olanzapine(2.5, 5 or 10 mg/kg) of olanzapine were orally administered to rats,followed by intraperitoneal administration of amphetamine. As is shownin FIGS. 29-31, while olanzapine was capable of substantiallyantagonizing the climbing behavior induced by amphetamine only at highdoses (10 mg/kg), almost no effect thereof was observed with respect tohead movements.

These results stand in line with the previously reported lower efficacyof olanzapine in the amphetamine model [15]. However, the data obtainedin these studies further suggest that the chemical conjugates of thepresent invention exert lower anti-dopaminergic activity, as comparedwith neuroleptic drugs and therefore may show some resembles to atypicaldrugs.

The data obtained in this model further support the high efficacy of theconjugates of the present invention in exerting psychotropic activitywhile reducing the adverse side effects induced by the parentpsychotropic drug.

The overall experimental results delineated hereinabove demonstrate thehigh and advantageous efficacy of the novel chemical conjugates of thepresent invention in exerting psychotropic activity, anti-proliferativeactivity and chemosensitizing activity, with minimized toxicity tonormal cells and minimized adverse side effects.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. All publications, patents and patentapplications mentioned in this specification are herein incorporated intheir entirety by reference into the specification, to the same extentas if each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present invention.

REFERENCES CITED BY NUMERALS Additional References are Cited in the Text

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1. A chemical conjugate consisting of a first chemical moiety covalentlylinked to a second chemical moiety, wherein said first chemical moietyis an anti-depressant selected from the group consisting of fluoxetineand nortriptyline, and said second chemical moiety is γ-aminobutyricacid (GABA), wherein said second chemical moiety is covalently linked tosaid first chemical moiety via an amide bond.
 2. A pharmaceuticalcomposition comprising, as an active ingredient, the chemical conjugateof claim 1 and a pharmaceutically acceptable carrier.
 3. Apharmaceutical composition being packaged in a packaging material andidentified in print, on or in the packaging material, for use in thetreatment of a psychotropic disorder or disease selected from the groupconsisting of an anxiety disorder and a mood disorder, the compositioncomprising, as an active ingredient, the chemical conjugate of claim 1and a pharmaceutically acceptable carrier.
 4. The pharmaceuticalcomposition of claim 3, wherein said psychotropic disorder or disease isselected from the group consisting of depression and anxiety.
 5. Amethod of treating a psychotropic disorder or disease selected from thegroup consisting of a mood disorder and an anxiety disorder in asubject, the method comprising administering to the subject atherapeutically effective amount of the chemical conjugate of claim 1.6. The method of claim 5, wherein said psychotropic disorder or diseaseis selected from the group consisting of depression and anxiety.
 7. Themethod of claim 5, wherein said chemical conjugate is administeredintraperitoneally.
 8. The method of claim 5, wherein said chemicalconjugate is administered orally.
 9. A method of synthesizing thechemical conjugate of claim 1, the method comprising: reacting saidorganic acid and said anti-depressant, so as to obtain said organic acidcovalently linked to said residue of said anti-depressant.
 10. Themethod of claim 9, wherein said organic acid is covalently linked tosaid anti-depressant via an amide bond, the method further comprising,prior to said reacting: converting a carboxylic acid group of saidorganic acid into an acyl chloride group; and converting a functionalgroup of said anti-depressant into an amine group.
 11. The method ofclaim 10, wherein said reacting is performed under basic conditions. 12.The method of claim 9, wherein said organic acid comprises a free aminogroup, the method further comprising: protecting said amino group with aprotecting group, prior to said reacting, so as to obtain by saidreacting an amino-protected organic acid covalently linked to saidanti-depressant; and removing said protecting group after obtaining saidamino-protected organic acid covalently linked to said anti-depressant.13. The method of claim 12, further comprising, after said protectingand prior to said reacting: converting a carboxylic acid group of saidorganic acid into an acyl imidazole group.